Graphene is a monolayer of carbon atoms constructing a two-dimensional honeycomb structure, and it has an excellent carrier mobility and a very high thermal conductivity. Remarkably, it has been experimentally demonstrated that a monolayer graphene exhibits an exotic optical properties. To be specific, the plasmonic dispersion relation of a transverse magnetic graphene plasmon is electronically tunable by adjusting carrier density in graphene with external gate bias, and graphene plasmonic nano cavities have been utilized to modulate mid-infrared light.
\r\n\r\nIn this thesis, we present how to efficiently modulate mid-infrared light by combining graphene plasmonic ribbons with noble metal plasmonic structures.
\r\n\r\nFirst, we propose and demonstrate electronically tunable resonant perfect absorption in graphene plasmonic metasurface enhanced by noble metal plasmonic effect, which results in modulating reflecting light. In this device, we improve coupling efficiency of free-space photons into graphene plasmons by reducing wavevector mismatching with a low permittivity substrate. In addition, the graphene plasmonic resonance is significantly enhanced by plasmonic light focusing effect of the coupled subwavelength metallic slit structure, which results in strongly fortifying resonance absorption in the graphene plasmonic metasurface. In the proposed device, theoretical calculation expects that perfect absorption in the graphene plasmonic metasurface is achievable with low graphene carrier mobility. We also present an analytical model based on surface admittance in order to fully understand how this enhancement occurs.
\r\n\r\nIn the second device, we propose and demonstrate a transmission type light modulator by combining graphene plasmonic ribbons with subwavelength metal slit arrays. In this device, extraordinary optical transmission resonance is coupled to graphene plasmonic ribbons to create electrostatic modulation of mid-infrared light. Absorption in graphene plasmonic ribbons situated inside metallic slits can efficiently block the coupling channel for resonant transmission, leading to a suppression of transmission. This phenomenon is also interpreted by anti-crossing between the graphene plasmonic resonance in the ribbons and the noble metal plasmonic resonance in the subwavelength metal slit arrays.
\r\n\r\nFinally, we devise a platform to demonstrate graphene plasmonic resonance energy transport along graphene plasmonic ribbons. In this device, two metal-insulator-metal waveguides are connected by a subwavelength metal slit, and graphene plasmonic ribbons are located inside this slit. Due to the large impedance mismatch at the junction, light coupling efficiency across the junction is poor. If the graphene plasmonic ribbons are tuned to support strong graphene plasmonic resonances, the light energy can be transferred via graphene plasmons along the ribbons, and it leads to significant improvement in the light coupling efficiency across the junction. In addition to enhanced light coupling efficiency, we also present how to totally suppress the transmission by inducing a Fano resonance between a non-resonant propagation mode across the junction and a resonant graphene plasmonic transport mode, which can be utilized to efficiently modulate light in a noble metal plasmonic waveguide with the graphene plasmon resonance energy transfer.
", "doi": "10.7907/Z9ZW1HXJ", "publication_date": "2017", "thesis_type": "phd", "thesis_year": "2017" }, { "id": "thesis:9818", "collection": "thesis", "collection_id": "9818", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05312016-211459301", "primary_object_url": { "basename": "liu_zhao_2016_thesis.pdf", "content": "final", "filesize": 11058862, "license": "other", "mime_type": "application/pdf", "url": "/9818/55/liu_zhao_2016_thesis.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Electromyographic Signal Processing With Application To Spinal Cord Injury", "author": [ { "family_name": "Liu", "given_name": "Zhao", "clpid": "Liu-Zhao" } ], "thesis_advisor": [ { "family_name": "Burdick", "given_name": "Joel Wakeman", "clpid": "Burdick-J-W" } ], "thesis_committee": [ { "family_name": "Burdick", "given_name": "Joel Wakeman", "clpid": "Burdick-J-W" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" }, { "family_name": "Edgerton", "given_name": "V. Reggie", "clpid": "Edgerton-V-R" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "An Electromyogram or Electromyographic (EMG) signal is the recording of the electrical activity produced by muscles. It measures the electric currents generated in muscles during their contraction. The EMG signal provides insight into the neural activation and dynamics of the muscles, and is therefore important for many different applications, such as in clinical investigations that attempt to diagnose neuromuscular deficiencies. In particular, the work in this thesis is motivated by rehabilitation for patients with spinal cord injury. The EMG signal is very important for researchers and practitioners to monitor and evaluate the effect of the rehabilitation training and the condition of muscles, as the EMG signal provides information that helps infer the neural activity in the spinal cord. Before the work in this thesis, EMG analysis required significant amounts of manual labeling of interesting signal features. The motivation of this thesis is to fully automate the EMG analysis tasks and yield accurate, consistent results.
\r\n\r\nThe EMG signal contains multiple muscle responses. The difficulty in processing the EMG signal arises from the fact that the transient muscle response is a transient signal with unknown arrival time, unknown duration, and unknown shape. In addition, the EMG signal recorded from patients with spinal cord injury during rehabilitation is very different from the EMG signal of normal healthy people undergoing the same motions. For example, some of the muscle responses are very weak and thus hard to detect. Because of this, general EMG processing tools and methods are either not applicable or insufficient.
\r\n\r\nThe primary contribution of this thesis is the development of a wavelet-based, double-threshold algorithm for the detection of transient peaks in the EMG signal. The application of wavelet transform in the detection of transient signals has been studied extensively and employed successfully. However, most of the theories assume certain knowledge about the shapes of the transient signals, which makes it hard to be generalized to the transient signals with arbitrary shapes. The proposed detection scheme focuses on the more fundamental feature of most transient signals (in particular the EMG signal): peaks, instead of the shapes. The continuous wavelet transform with Mexican Hat wavelet is employed. This thesis theoretically derived a framework for selecting a set of scales based on the frequency domain information. Ridges are identified in the time-scale space to combine the wavelet coefficients from different scales. By imposing two thresholds, one on the wavelet coefficient and one on the ridge length, the proposed detection scheme can achieve both high recall and high precision. A systematic approach for selecting the optimal parameters via simulation is proposed and demonstrated. Comparing with other state-of-the-art detection methods, the proposed method in this thesis yields a better detection performance, especially in the low Signal-to-Noise-Ratio (SNR) environment.
\r\n\r\nBased on the transient peak detection result, the EMG signal is further segmented and classified into various groups of monosynaptic Motor Evoked Potentials (MEPs) and polysynaptic MEPs using techniques stemming from Principal Component Analysis (PCA), hierarchical clustering, and Gaussian mixture model (GMM). A theoretical framework is proposed to segment the EMG signal based on the detected peaks. The scale information of the detected peak is used to derive a measure for its effective support. Several different techniques have been adapted together to solve the clustering problem. An initial hierarchical clustering is first performed to obtain most of the monosynaptic MEPs. PCA is used to reduce the number of features and the effect of the noise. The reduced feature set is then fed to a GMM to further divide the MEPs into different groups of similar shapes. The method of breaking down a segment of multiple consecutive MEPs into individual MEPs is derived.
\r\n\r\nA software with graphic user interface has been implemented in Matlab. The software implements the proposed peak detection algorithm, and enables the physiologists to visualize the detection results and modify them if necessary. The solutions proposed in this thesis are not only helpful to the rehabilitation after spinal cord injury, but applicable to other general processing tasks on transient signals, especially on biological signals.
", "doi": "10.7907/Z9QJ7F99", "publication_date": "2016", "thesis_type": "phd", "thesis_year": "2016" }, { "id": "thesis:9234", "collection": "thesis", "collection_id": "9234", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10212015-150203289", "primary_object_url": { "basename": "Thesis.pdf", "content": "final", "filesize": 109730024, "license": "other", "mime_type": "application/pdf", "url": "/9234/1/Thesis.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Holistic Design In High-Speed Optical Interconnects", "author": [ { "family_name": "Saeedi", "given_name": "Saman", "clpid": "Saeedi-Saman" } ], "thesis_advisor": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" } ], "thesis_committee": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Integrated circuit scaling has enabled a huge growth in processing capability, which necessitates a corresponding increase in inter-chip communication bandwidth. As bandwidth requirements for chip-to-chip interconnection scale, deficiencies of electrical channels become more apparent. Optical links present a viable alternative due to their low frequency-dependent loss and higher bandwidth density in the form of wavelength division multiplexing. As integrated photonics and bonding technologies are maturing, commercialization of hybrid-integrated optical links are becoming a reality. Increasing silicon integration leads to better performance in optical links but necessitates a corresponding co-design strategy in both electronics and photonics. In this light, holistic design of high-speed optical links with an in-depth understanding of photonics and state-of-the-art electronics brings their performance to unprecedented levels. This thesis presents developments in high-speed optical links by co-designing and co-integrating the primary elements of an optical link: receiver, transmitter, and clocking.
\r\n\r\nIn the first part of this thesis a 3D-integrated CMOS/Silicon-photonic receiver will be presented. The electronic chip features a novel design that employs a low-bandwidth TIA front-end, double-sampling and equalization through dynamic offset modulation. Measured results show -14.9dBm of sensitivity and energy efficiency of 170fJ/b at 25Gb/s. The same receiver front-end is also used to implement source-synchronous 4-channel WDM-based parallel optical receiver. Quadrature ILO-based clocking is employed for synchronization and a novel frequency-tracking method that exploits the dynamics of IL in a quadrature ring oscillator to increase the effective locking range. An adaptive body-biasing circuit is designed to maintain the per-bit-energy consumption constant across wide data-rates. The prototype measurements indicate a record-low power consumption of 153fJ/b at 32Gb/s. The receiver sensitivity is measured to be -8.8dBm at 32Gb/s.
\r\n\r\nNext, on the optical transmitter side, three new techniques will be presented. First one is a differential ring modulator that breaks the optical bandwidth/quality factor trade-off known to limit the speed of high-Q ring modulators. This structure maintains a constant energy in the ring to avoid pattern-dependent power droop. As a first proof of concept, a prototype has been fabricated and measured up to 10Gb/s. The second technique is thermal stabilization of micro-ring resonator modulators through direct measurement of temperature using a monolithic PTAT temperature sensor. The measured temperature is used in a feedback loop to adjust the thermal tuner of the ring. A prototype is fabricated and a closed-loop feedback system is demonstrated to operate at 20Gb/s in the presence of temperature fluctuations. The third technique is a switched-capacitor based pre-emphasis technique designed to extend the inherently low bandwidth of carrier injection micro-ring modulators. A measured prototype of the optical transmitter achieves energy efficiency of 342fJ/bit at 10Gb/s and the wavelength stabilization circuit based on the monolithic PTAT sensor consumes 0.29mW.
\r\n\r\nLastly, a first-order frequency synthesizer that is suitable for high-speed on-chip clock generation will be discussed. The proposed design features an architecture combining an LC quadrature VCO, two sample-and-holds, a PI, digital coarse-tuning, and rotational frequency detection for fine-tuning. In addition to an electrical reference clock, as an extra feature, the prototype chip is capable of receiving a low jitter optical reference clock generated by a high-repetition-rate mode-locked laser. The output clock at 8GHz has an integrated RMS jitter of 490fs, peak-to-peak periodic jitter of 2.06ps, and total RMS jitter of 680fs. The reference spurs are measured to be \u201364.3dB below the carrier frequency. At 8GHz the system consumes 2.49mW from a 1V supply.
", "doi": "10.7907/Z9K935HH", "publication_date": "2016", "thesis_type": "phd", "thesis_year": "2016" }, { "id": "thesis:8898", "collection": "thesis", "collection_id": "8898", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05282015-141343540", "primary_object_url": { "basename": "saFN999I9qeezyfjOAIBOSbqqbgW0lXJe8VCTAf7R624ttavA87cha2LoU7i0CUv", "content": "final", "filesize": 72440132, "license": "other", "mime_type": "application/pdf", "url": "/8898/1/saFN999I9qeezyfjOAIBOSbqqbgW0lXJe8VCTAf7R624ttavA87cha2LoU7i0CUv", "version": "v4.0.0" }, "type": "thesis", "title": "Instrumentation for Kinetic-Inductance-Detector-Based Submillimeter Radio Astronomy", "author": [ { "family_name": "Duan", "given_name": "Ran", "clpid": "Duan-Ran" } ], "thesis_advisor": [ { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" } ], "thesis_committee": [ { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "local_group": [ { "literal": "Astronomy Department" }, { "literal": "div_eng" } ], "abstract": "A substantial amount of important scientific information is contained within astronomical data at the submillimeter and far-infrared (FIR) wavelengths, including information regarding dusty galaxies, galaxy clusters, and star-forming regions; however, these wavelengths are among the least-explored\r\nfields in astronomy because of the technological difficulties involved in such research. Over the past 20 years, considerable efforts have been devoted to developing submillimeter- and millimeter-wavelength astronomical instruments and telescopes.
\r\n\r\nThe number of detectors is an important property of such instruments and is the subject of the current study. Future telescopes will require as many as hundreds of thousands of detectors to meet the necessary requirements in terms of the field of view, scan speed, and resolution. A large pixel count is one benefit of the development of multiplexable detectors that use kinetic inductance detector (KID) technology.
\r\n\r\nThis dissertation presents the development of a KID-based instrument including a portion of the millimeter-wave bandpass filters and all aspects of the readout electronics, which together enabled one of the largest detector counts achieved to date in submillimeter-/millimeter-wavelength imaging arrays: a total of 2304 detectors. The work presented in this dissertation has been implemented in the MUltiwavelength Submillimeter Inductance Camera (MUSIC), a new instrument for the Caltech Submillimeter Observatory (CSO).
", "doi": "10.7907/Z90P0WXZ", "publication_date": "2015", "thesis_type": "phd", "thesis_year": "2015" }, { "id": "thesis:8965", "collection": "thesis", "collection_id": "8965", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06022015-015750109", "primary_object_url": { "basename": "CFC_Thesis_2015-revised.pdf", "content": "final", "filesize": 14422388, "license": "other", "mime_type": "application/pdf", "url": "/8965/7/CFC_Thesis_2015-revised.pdf", "version": "v7.0.0" }, "type": "thesis", "title": "Wafer-Scalable Fabrication of Metal Nanostructures for Plasmonics-Assisted Biomedical Sensing Applications", "author": [ { "family_name": "Chang", "given_name": "Chieh-Feng", "clpid": "Chang-Chieh-Feng" } ], "thesis_advisor": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "thesis_committee": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Fraser", "given_name": "Scott E.", "clpid": "Fraser-S-E" }, { "family_name": "Walavalkar", "given_name": "Sameer S.", "clpid": "Walavalkar-S-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Plasmonics provides many opportunities of sensing and detection since it combines the nanoscale spatial confinement and the optical temporal resolution. The wireless nature of photonic investigation, moreover, is very desirable for biomedical applications. Plasmonic metals, however, are difficult to pattern with great nanoscopic precision, and traditional approaches were time-consuming, non-scalable, stochastically-manufactured, or highly-limiting in the pattern designs. In this work, wafer-scalable nanofabrication methods are presented for various plasmonic structures for biomedical sensing applications. The fabrication steps have ready counterparts in commercial semiconductor foundries and therefore can be directly applied for mass production.
\r\n\r\nThe fabrication and measurement of extraordinary transmission (EOT) are discussed in Chapter 2. Fabrication options are available for substrates like silicon-on-sapphire and silicon-on-glass, so that the devices can be mechanically robust for user-friendliness. The metal layer can also be varied for EOT applications in different ranges of wavelengths. The EOT nanostructures can be fabricated to be polarization-sensitive, and the concept of fluorescence-based EOT assays is demonstrated.
\r\n\r\nThe fabrication and applications of surface-enhanced Raman spectroscopy (SERS) are then discussed. With a hybrid approach, the top-down designing defines uniform SERS nanostructures on a chip, while the bottom-up process of thermal reflow increases the fabrication precision beyond the lithography resolution limit. Based on the thiophenol study, an enhancement factor greater than 1010 can be achieved. The first Raman spectrum of tracheal cytotoxin is demonstrated without any special sample preparation, and thrombin binding could be easily resolved through chip functionalization. The binding dynamics of ethyl mercaptan, which is similar to the highly toxic gas of hydrogen sulfide, can be detected with a good resolution in time at a low concentration.
\r\n\r\nWith a few more steps of fabrication, the plasmonic structures can be integrated into systems that do not call for laboratory infrastructures. A built-in micro-channel on a chip can make the device useful without dedicated support of a microscope or additional microfluidic structures. The nanostructures can also be transferred onto flexible substrates for better conformity onto various surfaces. Finally, the SERS structures can be transferred onto a fiber tip for in-field or through-the-needle applications, especially when combined with a portable Raman-scope.
", "doi": "10.7907/Z9K935FM", "publication_date": "2015", "thesis_type": "phd", "thesis_year": "2015" }, { "id": "thesis:8717", "collection": "thesis", "collection_id": "8717", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10282014-113257585", "primary_object_url": { "basename": "KaushikThesis.pdf", "content": "final", "filesize": 22700825, "license": "other", "mime_type": "application/pdf", "url": "/8717/1/KaushikThesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Self-Healing Techniques for RF and mm-Wave Transmitters and Receivers", "author": [ { "family_name": "Dasgupta", "given_name": "Kaushik", "clpid": "Dasgupta-Kaushik" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "With continuing advances in CMOS technology, feature sizes of modern Silicon chip-sets have gone down drastically over the past decade. In addition to desktops and laptop processors, a vast majority of these chips are also being deployed in mobile communication devices like smart-phones and tablets, where multiple radio-frequency integrated circuits (RFICs) must be integrated into one device to cater to a wide variety of applications such as Wi-Fi, Bluetooth, NFC, wireless charging, etc. While a small feature size enables higher integration levels leading to billions of transistors co-existing on a single chip, it also makes these Silicon ICs more susceptible to variations. A part of these variations can be attributed to the manufacturing process itself, particularly due to the stringent dimensional tolerances associated with the lithographic steps in modern processes. Additionally, RF or millimeter-wave communication chip-sets are subject to another type of variation caused by dynamic changes in the operating environment. Another bottleneck in the development of high performance RF/mm-wave Silicon ICs is the lack of accurate analog/high-frequency models in nanometer CMOS processes. This can be primarily attributed to the fact that most cutting edge processes are geared towards digital system implementation and as such there is little model-to-hardware correlation at RF frequencies.
\r\n\r\nAll these issues have significantly degraded yield of high performance mm-wave and RF CMOS systems which often require multiple trial-and-error based Silicon validations, thereby incurring additional production costs. This dissertation proposes a low overhead technique which attempts to counter the detrimental effects of these variations, thereby improving both performance and yield of chips post fabrication in a systematic way. The key idea behind this approach is to dynamically sense the performance of the system, identify when a problem has occurred, and then actuate it back to its desired performance level through an intelligent on-chip optimization algorithm. We term this technique as self-healing drawing inspiration from nature's own way of healing the body against adverse environmental effects. To effectively demonstrate the efficacy of self-healing in CMOS systems, several representative examples are designed, fabricated, and measured against a variety of operating conditions.
\r\n\r\nWe demonstrate a high-power mm-wave segmented power mixer array based transmitter architecture that is capable of generating high-speed and non-constant envelope modulations at higher efficiencies compared to existing conventional designs. We then incorporate several sensors and actuators into the design and demonstrate closed-loop healing against a wide variety of non-ideal operating conditions. We also demonstrate fully-integrated self-healing in the context of another mm-wave power amplifier, where measurements were performed across several chips, showing significant improvements in performance as well as reduced variability in the presence of process variations and load impedance mismatch, as well as catastrophic transistor failure. Finally, on the receiver side, a closed-loop self-healing phase synthesis scheme is demonstrated in conjunction with a wide-band voltage controlled oscillator to generate phase shifter local oscillator (LO) signals for a phased array receiver. The system is shown to heal against non-idealities in the LO signal generation and distribution, significantly reducing phase errors across a wide range of frequencies.
", "doi": "10.7907/Z9HQ3WTR", "publication_date": "2015", "thesis_type": "phd", "thesis_year": "2015" }, { "id": "thesis:8719", "collection": "thesis", "collection_id": "8719", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:11062014-090236636", "type": "thesis", "title": "Injection Locked Clocking and Transmitter Equalization Techniques for Chip to Chip Interconnects", "author": [ { "family_name": "Raj", "given_name": "Mayank", "clpid": "Raj-Mayank" } ], "thesis_advisor": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" } ], "thesis_committee": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Semiconductor technology scaling has enabled drastic growth in the computational capacity of integrated circuits (ICs). This constant growth drives an increasing demand for high bandwidth communication between ICs. Electrical channel bandwidth has not been able to keep up with this demand, making I/O link design more challenging. Interconnects which employ optical channels have negligible frequency dependent loss and provide a potential solution to this I/O bandwidth problem. Apart from the type of channel, efficient high-speed communication also relies on generation and distribution of multi-phase, high-speed, and high-quality clock signals. In the multi-gigahertz frequency range, conventional clocking techniques have encountered several design challenges in terms of power consumption, skew and jitter. Injection-locking is a promising technique to address these design challenges for gigahertz clocking. However, its small locking range has been a major contributor in preventing its ubiquitous acceptance.
\r\n \r\nIn the first part of this dissertation we describe a wideband injection locking scheme in an LC oscillator. Phase locked loop (PLL) and injection locking elements are combined symbiotically to achieve wide locking range while retaining the simplicity of the latter. This method does not require a phase frequency detector or a loop filter to achieve phase lock. A mathematical analysis of the system is presented and the expression for new locking range is derived. A locking range of 13.4 GHz\u201317.2 GHz (25%) and an average jitter tracking bandwidth of up to 400 MHz are measured in a high-Q LC oscillator. This architecture is used to generate quadrature phases from a single clock without any frequency division. It also provides high frequency jitter filtering while retaining the low frequency correlated jitter essential for forwarded clock receivers.
\r\n\r\nTo improve the locking range of an injection locked ring oscillator; QLL (Quadrature locked loop) is introduced. The inherent dynamics of injection locked quadrature ring oscillator are used to improve its locking range from 5% (7-7.4GHz) to 90% (4-11GHz). The QLL is used to generate accurate clock phases for a four channel optical receiver using a forwarded clock at quarter-rate. The QLL drives an injection locked oscillator (ILO) at each channel without any repeaters for local quadrature clock generation. Each local ILO has deskew capability for phase alignment. The optical-receiver uses the inherent frequency to voltage conversion provided by the QLL to dynamically body bias its devices. A wide locking range of the QLL helps to achieve a reliable data-rate of 16-32Gb/s and adaptive body biasing aids in maintaining an ultra-low power consumption of 153pJ/bit.
\r\n \r\nFrom the optical receiver we move on to discussing a non-linear equalization technique for a vertical-cavity surface-emitting laser (VCSEL) based optical transmitter, to enable low-power, high-speed optical transmission. A non-linear time domain optical model of the VCSEL is built and evaluated for accuracy. The modelling shows that, while conventional FIR-based pre-emphasis works well for LTI electrical channels, it is not optimum for the non-linear optical frequency response of the VCSEL. Based on the simulations of the model an optimum equalization methodology is derived. The equalization technique is used to achieve a data-rate of 20Gb/s with power efficiency of 0.77pJ/bit.
\r\n", "doi": "10.7907/Z90P0WZD", "publication_date": "2015", "thesis_type": "phd", "thesis_year": "2015" }, { "id": "thesis:8896", "collection": "thesis", "collection_id": "8896", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05282015-121920930", "primary_object_url": { "basename": "PhDthesis_final_Chenguang Ji_05182015.pdf", "content": "final", "filesize": 3357230, "license": "other", "mime_type": "application/pdf", "url": "/8896/1/PhDthesis_final_Chenguang Ji_05182015.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Design of Antenna-Coupled Lumped-Element Titanium Nitride KIDs for LongWavelength Multi-Band Continuum Imaging", "author": [ { "family_name": "Ji", "given_name": "Chenguang", "clpid": "Ji-Chenguang" } ], "thesis_advisor": [ { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" } ], "thesis_committee": [ { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" }, { "family_name": "Goddard", "given_name": "William A., III", "clpid": "Goddard-W-A-III" }, { "family_name": "Johnson", "given_name": "William L.", "clpid": "Johnson-W-L" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" } ], "local_group": [ { "literal": "Astronomy Department" }, { "literal": "div_eng" } ], "abstract": "Many applications in cosmology and astrophysics at millimeter wavelengths including CMB polarization, studies of galaxy clusters using the Sunyaev-Zeldovich effect (SZE), and studies of star formation at high redshift and in our local universe and our galaxy, require large-format arrays of millimeter-wave detectors. Feedhorn and phased-array antenna architectures for receiving mm-wave light present numerous advantages for control of systematics, for simultaneous coverage of both polarizations and/or multiple spectral bands, and for preserving the coherent nature of the incoming light. This enables the application of many traditional \"RF\" structures such as hybrids, switches,\r\nand lumped-element or microstrip band-defining filters.
\r\n\r\nSimultaneously, kinetic inductance detectors (KIDs) using high-resistivity materials like titanium nitride are an attractive sensor option for large-format arrays because they are highly multiplexable and because they can have sensitivities reaching the condition of background-limited detection. A\r\nKID is a LC resonator. Its inductance includes the geometric inductance and kinetic inductance of the inductor in the superconducting phase. A photon absorbed by the superconductor breaks a Cooper pair into normal-state electrons and perturbs its kinetic inductance, rendering it a detector\r\nof light. The responsivity of KID is given by the fractional frequency shift of the LC resonator per unit optical power.
\r\n\r\nHowever, coupling these types of optical reception elements to KIDs is a challenge because of the impedance mismatch between the microstrip transmission line exiting these architectures and the high resistivity of titanium nitride. Mitigating direct absorption of light through free space coupling to the inductor of KID is another challenge. We present a detailed titanium nitride KID\r\ndesign that addresses these challenges. The KID inductor is capacitively coupled to the microstrip in such a way as to form a lossy termination without creating an impedance mismatch. A parallel plate capacitor design mitigates direct absorption, uses hydrogenated amorphous silicon, and yields acceptable noise. We show that the optimized design can yield expected sensitivities very close to\r\nthe fundamental limit for a long wavelength imager (LWCam) that covers six spectral bands from 90 to 400 GHz for SZE studies.
\r\n\r\nExcess phase (frequency) noise has been observed in KID and is very likely caused by two-level systems (TLS) in dielectric materials. The TLS hypothesis is supported by the measured dependence of the noise on resonator internal power and temperature. However, there is still a lack of a unified microscopic theory which can quantitatively model the properties of the TLS noise. In this thesis we\r\nderive the noise power spectral density due to the coupling of TLS with phonon bath based on an existing model and compare the theoretical predictions about power and temperature dependences with experimental data. We discuss the limitation of such a model and propose the direction for future study.
", "doi": "10.7907/Z9W66HQ7", "publication_date": "2015", "thesis_type": "phd", "thesis_year": "2015" }, { "id": "thesis:8944", "collection": "thesis", "collection_id": "8944", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05302015-005943888", "primary_object_url": { "basename": "Pai_Alex_2015_06_12_thesis.pdf", "content": "final", "filesize": 35439405, "license": "other", "mime_type": "application/pdf", "url": "/8944/1/Pai_Alex_2015_06_12_thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Sensing and Actuation from Biology to Electronics", "author": [ { "family_name": "Pai", "given_name": "Alex Hao-Yu", "clpid": "Pai-Alex-Hao-Yu" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "We introduce an in vitro diagnostic magnetic biosensing platform for immunoassay and nucleic acid detection. The platform has key characteristics for a point-of-use (POU) diagnostic: portability, low-power consumption, low cost, and multiplexing capability. As a demonstration of capabilities, we use this platform for the room temperature, amplification-free detection of a 31 bp DNA oligomer and interferon-gamma (a protein relevant for tuberculosis diagnosis). Reliable assay measurements down to 100 pM for the DNA and 1 pM for the protein are demonstrated. We introduce a novel \"magnetic freezing\" technique for baseline measurement elimination and to enable spatial multiplexing. We have created a general protocol for adapting integrated circuit (IC) sensors to any of hundreds of commercially available immunoassay kits and custom designed DNA sequences.
\r\n\r\nWe also introduce a method for immunotherapy treatment of malignant gliomas. We utilize leukocytes internalized with immunostimulatory nanoparticle-oligonucleotide conjugates to localize and retain immune cells near the tumor site. As a proof-of-principle, we develop a novel cell imaging and incubation chamber for in vitro magnetic motility experiments. We use the apparatus to demonstrate the controlled movement of magnetically loaded THP-1 leukocytes.
\r\n\r\nFinally, we introduce an IC transmitter and power ampli er (PA) that utilizes electronic digital infrastructure, sensors, and actuators to self-heal and adapt to process, dynamic, and environmental variation. Traditional IC design has achieved incredible degrees of reliability by ensuring that billions of transistors on a single IC die are all simultaneously functional. Reliability becomes increasingly difficult as the size of a transistor shrinks. Self-healing can mitigate these variations.
", "doi": "10.7907/Z9NC5Z5M", "publication_date": "2015", "thesis_type": "phd", "thesis_year": "2015" }, { "id": "thesis:8497", "collection": "thesis", "collection_id": "8497", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06062014-160929992", "primary_object_url": { "basename": "Muhammad_Mujeeb_U_Rahman_PhD_Thesis_Final.pdf", "content": "final", "filesize": 7117031, "license": "other", "mime_type": "application/pdf", "url": "/8497/1/Muhammad_Mujeeb_U_Rahman_PhD_Thesis_Final.pdf", "version": "v8.0.0" }, "type": "thesis", "title": "Integrated Microsystems for Wireless Sensing Applications", "author": [ { "family_name": "Mujeeb-U-Rahman", "given_name": "Muhammad", "clpid": "Mujeeb-U-Rahman-Muhammad" } ], "thesis_advisor": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "thesis_committee": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Fraser", "given_name": "Scott E.", "clpid": "Fraser-S-E" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" } ], "local_group": [ { "literal": "Kavli Nanoscience Institute" }, { "literal": "div_eng" } ], "abstract": "Personal health monitoring is being considered the future of a sustainable health care system. Biosensing platforms are a very important component of this system. Real-time and accurate sensing is essential for the success of personal health care model. Currently, there are many efforts going on to make these sensors practical and more useful for such measurements. Implantable sensors are considered the most widely applicable and most reliable sensors for such accurate health monitoring applications. However, macroscopic (cm scale) size has proved to be a limiting factor for successful use of these systems for long time and in large numbers. This work is focused to resolve the issues related with miniaturizing these devices to a microscopic (mm scale) size scale which can minimize many practical difficulties associated with their larger counterparts currently.
\r\n\r\nTo accomplish this goal of miniaturization while retaining or even improving on the necessary capabilities for such sensing platforms, an integrated approach is presented which focuses on system-level miniaturization using standard fabrication procedures. First, it is shown that a completely integrated and wireless system is the best solution to achieve desired miniaturization without sacrificing the functionality of the system. Hence, design and implementation of the different components comprising the complete system needs to be done according to the requirements of the overall integrated system. This leads to the need of on-chip functional sensors, integrated wireless power supply, integrated wireless communication and integrated control system for realization of such system. In this work, different options for implementation of each of these subsystems are compared and an optimal solution is presented for each subsystem. For such complex systems, it is imperative to use a standard fabrication process which can provide the required functionality for all subsystems at smallest possible size scale. Complementary Metal Oxide Semiconductor (CMOS) process is the most appropriate of the technologies in this regard and has enabled incredible miniaturization of the computing industry. It also provides options for designing different subsystems on the same platform in a monolithic process with very high yield. This choice then leads to actual designs of subsystems in the CMOS technology using different possible methods. Careful comparison of these subsystems provides insights into different design adjustments that are made until the desired functions are achieved at the desired size scale. Integration of all these compatible subsystems in the same platform is shown to provide the smallest possible sensing platform to date.
\r\n\r\nThe completely wireless system can measure a host of different important analyte and can transmit the data to an external device which can use it for appropriate purpose. Results on measurements in phosphate buffer solution, blood serum and whole blood along with wireless communication in real biological tissues are provided. Specific examples of glucose and DNA sensors are presented and the use for many other relevant applications is also proposed. Finally, insights into animal model studies and future directions of the research are discussed.
\r\n", "doi": "10.7907/Z98050MN", "publication_date": "2014", "thesis_type": "phd", "thesis_year": "2014" }, { "id": "thesis:8494", "collection": "thesis", "collection_id": "8494", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06062014-102704108", "primary_object_url": { "basename": "POC MDx FOR HUMANITY.pdf", "content": "final", "filesize": 12308510, "license": "other", "mime_type": "application/pdf", "url": "/8494/1/POC MDx FOR HUMANITY.pdf", "version": "v7.0.0" }, "type": "thesis", "title": "Point of Care Molecular Diagnostics for Humanity", "author": [ { "family_name": "Malik", "given_name": "Imran Raouf", "clpid": "Malik-Imran-Raouf" } ], "thesis_advisor": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "thesis_committee": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" }, { "family_name": "Joyce", "given_name": "Gerald", "clpid": "Joyce-G" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Diagnostics of disease at POC (point of care) has been declared one of the Grand Challenge by the Bill and Melina Gates Foundation (BMGF). Infectious diseases constitute a major cause of disease burden and cause more than half a billion Disability-Adjusted Life Years (DALYs) and millions of deaths each year. They have an especially large effect on children under 5 years of age. We have analyzed data from the GBD 2010 (Global Burden of Disease) project to emphasize the damage caused by infectious diseases, and highlight the opportunity of using diagnostic tools to rapidly identify and treat diseases. To motivate the work of this thesis, we quantify the expected impact of appropriate diagnostic technologies.
\r\n\r\nWe have also analyzed the requirements that a diagnostic tool should meet to generate the maximal global impact. We present various existing TPPs (Target Product Profiles) from different organizations and suggest some additions to these existing TPPs. We explain the particular molecular pathology technologies which have the potential to allow deployment of functional products in the developing world for point-of-care pathogen detection, especially in low-resource settings.
\r\n \r\nWe perform a detailed analysis on existing polymerase chain reaction (PCR) systems and describe the problems caused with thermal performance and optical interrogation. We list the requirements that disposable cartridges for such instruments should meet and suggest a metal base design with polymer top. After detailed FEA simulations, we demonstrate that the thermal response can be modeled using a one-dimensional (1D) lumped element system. We show improvements in thermal response due to using a metal base and the effect of fluid height. We also performed thermal-structural simulations to quantify the stresses on the adhesive bonds of metal/polymer cartridges.\r\nNext, we explain fabrication of these cartridges. We show methods to dispense adhesive using a robot and a custom made jig to spread the adhesive during curing. The cartridge was tested with different PCR reagents and we obtained reaction efficiencies approaching those of the commercial real time PCR machines. Our fabrication technique is useful to join dissimilar materials and is production friendly. By developing custom software, we observed the cartridge performance in a continuous manner. We could see the thermal response of cartridges by continuous fluorescence monitoring, and used reflective aluminum which increase light collection efficiency.
\r\n\r\nWe then present a simple and robust new way for thermal cycling. Robust thermal cycling has been a major challenge conducting PCR, especially in point of care situations. Here, we suggest a contact cooling approach, in which the cartridge rests on a thin metal plate with an integrated thin heater constructed from flexible printed circuit board (PCB) material. We use a solenoid to move a metal plate to cool down the sample cartridge during cycling. The metal plate then rests on a larger heat sink to disperse the shuttled heat. Our design is dust and water proof and was verified on a bench-top prototype.
\r\n\r\nA novel optical design for fluorescence detection during qPCR is also described. We suggest a lateral illumination waveguide geometry with prism coupling that eliminates lenses and is integrated into an injection molded cartridge. The light is homogenized using a light guide, and we quantify the sources of scattered stray light from the chamber edge by performing ray tracing simulations to optimize the precise geometry. The design is tolerant to misalignments and enables easy coupling of LED light into the chamber. As the light collection efficiency is high, the size of the chamber can be very small. We tested real PCR reactions using this concept and observed a rapid integration time, enabling very fast reading.
\r\n\r\nSample preparation has been another challenge for all point-of-care (POC) lab-on-chip devices for many years. Here, we propose a new design which is robust, fast, flexible and simple, and uses a sliding seal to move the collected sample between various reservoir chambers. The sample moves on a slider sandwiched between seals that shuttles a DNA binding membrane between different reactions. Thus, size and volumes of reagents can be increased without increasing dead volumes. This design is easily automated, and positive displacement of fluids can work with many reagents without worrying about their characteristics such as foaming. The speed of the sample preparation protocols is high and complex protocols can be ported on this design concept, which we tested on real clinical samples and obtained impressive results. We designed and injection molded devices to test and verify this concept.
\r\n\r\nFinally, we focus on instrumentation and software required to allow our technology to be used at the POC. We describe our embedded electronics and describe the powerful micro-controller and various high performance ICs that are used to construct a fully functional for sample to answer instrument. We developed various versions of software. The developer software allows us to control our system and bench top setup. Our end user product includes a tablet and cell phone software interface. Software was developed for a windows 8 tablet, windows 8 phone and an Android based devices.
\r\n\r\nTo conclude, we very briefly describe the POC systems that are under development: A portable qPCR system with a separate cartridge design, and a universal sample to answer system that performs qPCR, sample preparation and sample to answer protocols in one box depending on the cartridge.
\r\n\r\nAs per best of our knowledge the cost of this technology is much lower than any other option in its class. The sample to answer instrument is expected to cost less than $500. The test cost is expected to be less than $5. The performance is not compromised. We hope that this work can help bring a transformative change in the practice of pathology especially in the developing world.
\r\n", "doi": "10.7907/Z9HH6H2D", "publication_date": "2014", "thesis_type": "phd", "thesis_year": "2014" }, { "id": "thesis:8491", "collection": "thesis", "collection_id": "8491", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06052014-214022941", "type": "thesis", "title": "Microfabricated Tools and Engineering Methods for Sensing Bioanalytes", "author": [ { "family_name": "Rajagopal", "given_name": "Aditya", "clpid": "Rajagopal-Aditya" } ], "thesis_advisor": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "thesis_committee": [ { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" }, { "family_name": "Fraser", "given_name": "Scott E.", "clpid": "Fraser-S-E" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Baltimore", "given_name": "David L.", "clpid": "Baltimore-D-L" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "There is a convergence between the needs of the medical community and the capabilities of the engineering community. For example, the scale of biomedical devices and sensors allow for finer, more cost-effective quantification of biological and chemical targets. By using micro-fabrication techniques, we design and demonstrate a variety of microfluidic sensors and actuators that allow us to interact with a biochemical environment. We demonstrate the performance of microfluidic blood-filtrations chips, immune-diagnostic assays, and evaporative coolers. Furthermore, we show how micro-fabricated platinum filaments can be used for highly localized heating and temperature measurement. We demonstrate that these filaments can be used as miniature IR spectroscopic sources. Finally, we describe and demonstrate novel combinatorial coding methods for increasing the information extracted from biochemical reactions. We show proof-principle of these techniques in the context of Taqman PCR as well as persistence length PCR.", "doi": "10.7907/Z9W9575D", "publication_date": "2014", "thesis_type": "phd", "thesis_year": "2014" }, { "id": "thesis:7988", "collection": "thesis", "collection_id": "7988", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10102013-145125571", "primary_object_url": { "basename": "BowersThesis_Oct9_2013.pdf", "content": "final", "filesize": 11580240, "license": "other", "mime_type": "application/pdf", "url": "/7988/1/BowersThesis_Oct9_2013.pdf", "version": "v6.0.0" }, "type": "thesis", "title": "Dynamically Controllable Integrated Radiation and Self-Correcting Power Generation in mm-Wave Circuits and Systems", "author": [ { "family_name": "Bowers", "given_name": "Steven Michael", "clpid": "Bowers-Steven-Michael" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents novel design methodologies for integrated radiators and power generation at mm-wave frequencies that are enabled by the continued integration of various electronic and electromagnetic (EM) structures onto the same substrate. Beginning with the observation that transistors and their connections to EM radiating structures on an integrated substrate are essentially free, the concept of multi-port driven (MPD) radiators is introduced, which opens a vast design space that has been generally ignored due to the cost structure associated with discrete components that favors fewer transistors connected to antennas through a single port.
\r\n\r\nFrom Maxwell's equations, a new antenna architecture, the radial MPD antennas based on the concept of MPD radiators, is analyzed to gain intuition as to the important design parameters that explain the wide-band nature of the antenna itself. The radiator is then designed and implemented at 160 GHz in a 0.13 um SiGe BiCMOS process, and the single element design has a measured effective isotropic radiated power (EIRP) of +4.6 dBm with a total radiated power of 0.63 mW.
\r\n\r\nNext, the radial MPD radiator is adapted to enable dynamic polarization control (DPC). A DPC antenna is capable of controlling its radiated polarization dynamically, and entirely electronically, with no mechanical reconfiguration required. This can be done by having multiple antennas with different polarizations, or within a single antenna that has multiple drive points, as in the case of the MPD radiator with DPC. This radiator changes its polarization by adjusting the relative phase and amplitude of its multiple ports to produce polarizations with any polarization angle, and a wide range of axial ratios. A 2x1 MPD radiator array with DPC at 105 GHz is presented whose measurements show control of the polarization angle throughout the entire 0 degree through 180 degree range while in the linear polarization mode and maintaining axial ratios above 10 dB in all cases. Control of the axial ratio is also demonstrated with a measured range from 2.4 dB through 14 dB, while maintaining a fixed polarization angle. The radiator itself has a measured maximum EIRP of +7.8 dBm, with a total radiated power of 0.9 mW, and is capable of beam steering.
\r\n \r\nMPD radiators were also applied in the domain of integrated silicon photonics. For these designs, the driver transistor circuitry was replaced with silicon optical waveguides and photodiodes to produce a 350 GHz signal. Three of these optical MPD radiator designs have been implemented as 2x2 arrays at 350 GHz. The first is a beam forming array that has a simulated gain of 12.1 dBi with a simulated EIRP of -2 dBm. The second has the same simulated performance, but includes optical phase modulators that enable two-dimensional beam steering. Finally, a third design incorporates multi-antenna DPC by combining the outputs of both left and right handed circularly polarized MPD antennas to produce a linear polarization with controllable polarization angle, and has a simulated gain of 11.9 dBi and EIRP of -3 dBm. In simulation, it can tune the polarization from 0 degrees through 180 degrees while maintaining a radiated power that has a 0.35 dB maximum deviation from the mean.
\r\n\r\nThe reliability of mm-wave radiators and power amplifiers was also investigated, and two self-healing systems have been proposed. Self-healing is a global feedback method where integrated sensors detect the performance of the circuit after fabrication and report that data to a digital control algorithm. The algorithm then is capable of setting actuators that can control the performance of the mm-wave circuit and counteract any performance degradation that is observed by the sensors. The first system is for a MPD radiator array with a partially integrated self-healing system. The self-healing MPD radiator senses substrate modes through substrate mode pickup sensors and infers the far-field radiated pattern from those sensors. DC current sensors are also included to determine the DC power consumption of the system. Actuators are implemented in the form of phase and amplitude control of the multiple drive points.
\r\n\r\nThe second self-healing system is a fully integrated self-healing power amplifier (PA) at 28 GHz. This system measures the output power, gain and efficiency of the PA using radio frequency (RF) power sensors, DC current sensors and junction temperature sensors. The digital block is synthesized from VHDL code on-chip and it can actuate the output power combining matching network using tunable transmission line stubs, as well as the DC operating point of the amplifying transistors through bias control. Measurements of 20 chips confirm self-healing for two different algorithms for process variation and transistor mismatch, while measurements from 10 chips show healing for load impedance mismatch, and linearity healing. Laser induced partial and total transistor failure show the benefit of self-healing in the case of catastrophic failure, with improvements of up to 3.9 dB over the default case. An exemplary yield specification shows self-healing improving the yield from 0% up through 80%.
", "doi": "10.7907/Z9MP518K", "publication_date": "2014", "thesis_type": "phd", "thesis_year": "2014" }, { "id": "thesis:8456", "collection": "thesis", "collection_id": "8456", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05312014-143352981", "type": "thesis", "title": "Development of Integrated Parylene Fluidic Devices for Use as a Microbial Monitoring System in Wastewater Treatment", "author": [ { "family_name": "Satsanarukkit", "given_name": "Penvipha", "clpid": "Satsanarukkit-Penvipha" } ], "thesis_advisor": [ { "family_name": "Hoffmann", "given_name": "Michael R.", "orcid": "0000-0001-6495-1946", "clpid": "Hoffmann-M-R" } ], "thesis_committee": [ { "family_name": "Hoffmann", "given_name": "Michael R.", "orcid": "0000-0001-6495-1946", "clpid": "Hoffmann-M-R" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Doyle", "given_name": "John Comstock", "orcid": "0000-0002-1828-2486", "clpid": "Doyle-J-C" }, { "family_name": "Newman", "given_name": "Dianne K.", "orcid": "0000-0003-1647-1918", "clpid": "Newman-D-K" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "[Abstract Embargoed]", "doi": "10.7907/Z98G8HPQ", "publication_date": "2014", "thesis_type": "phd", "thesis_year": "2014" }, { "id": "thesis:7644", "collection": "thesis", "collection_id": "7644", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04292013-140750287", "primary_object_url": { "basename": "Akgiray_PhDThesis_FinalVersion.pdf", "content": "final", "filesize": 22979327, "license": "other", "mime_type": "application/pdf", "url": "/7644/1/Akgiray_PhDThesis_FinalVersion.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "New Technologies Driving Decade-Bandwidth Radio Astronomy: Quad-ridged Flared Horn and Compound-Semiconductor LNAs", "author": [ { "family_name": "Akgiray", "given_name": "Ahmed Halid", "clpid": "Akgiray-Ahmed-Halid" } ], "thesis_advisor": [ { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "thesis_committee": [ { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "Imbriale", "given_name": "William A.", "clpid": "Imbriale-W-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Among the branches of astronomy, radio astronomy is unique in that it spans the largest portion of the electromagnetic spectrum, e.g., from about 10 MHz to 300 GHz. On the other hand, due to scientific priorities as well as technological limitations, radio astronomy receivers have traditionally covered only about an octave bandwidth. This approach of \"one specialized receiver for one primary science goal\" is, however, not only becoming too expensive for next-generation radio telescopes comprising thousands of small antennas, but also is inadequate to answer some of the scientific questions of today which require simultaneous coverage of very large bandwidths.
\r\n\r\nThis thesis presents significant improvements on the state of the art of two key receiver components in pursuit of decade-bandwidth radio astronomy: 1) reflector feed antennas; 2) low-noise amplifiers on compound-semiconductor technologies. The first part of this thesis introduces the quadruple-ridged flared horn, a flexible, dual linear-polarization reflector feed antenna that achieves 5:1-7:1 frequency bandwidths while maintaining near-constant beamwidth. The horn is unique in that it is the only wideband feed antenna suitable for radio astronomy that: 1) can be designed to have nominal 10 dB beamwidth between 30 and 150 degrees; 2) requires one single-ended 50 Ohm low-noise amplifier per polarization. Design, analysis, and measurements of several quad-ridged horns are presented to demonstrate its feasibility and flexibility.
\r\n\r\nThe second part of the thesis focuses on modeling and measurements of discrete high-electron mobility transistors (HEMTs) and their applications in wideband, extremely low-noise amplifiers. The transistors and microwave monolithic integrated circuit low-noise amplifiers described herein have been fabricated on two state-of-the-art HEMT processes: 1) 35 nm indium phosphide; 2) 70 nm gallium arsenide. DC and microwave performance of transistors from both processes at room and cryogenic temperatures are included, as well as first-reported measurements of detailed noise characterization of the sub-micron HEMTs at both temperatures. Design and measurements of two low-noise amplifiers covering 1--20 and 8\u201450 GHz fabricated on both processes are also provided, which show that the 1--20 GHz amplifier improves the state of the art in cryogenic noise and bandwidth, while the 8--50 GHz amplifier achieves noise performance only slightly worse than the best published results but does so with nearly a decade bandwidth.
\r\n", "doi": "10.7907/TYX5-2C48", "publication_date": "2013", "thesis_type": "phd", "thesis_year": "2013" }, { "id": "thesis:7286", "collection": "thesis", "collection_id": "7286", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:11262012-212534634", "primary_object_url": { "basename": "DSRussell_Thesis_2012.pdf", "content": "final", "filesize": 16046459, "license": "other", "mime_type": "application/pdf", "url": "/7286/1/DSRussell_Thesis_2012.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Technology Advances for Radio Astronomy", "author": [ { "family_name": "Russell", "given_name": "Damon Stuart", "clpid": "Russell-Damon-Stuart" } ], "thesis_advisor": [ { "family_name": "Weinreb", "given_name": "Sander", "orcid": "0000-0002-9353-6204", "clpid": "Weinreb-S" } ], "thesis_committee": [ { "family_name": "Weinreb", "given_name": "Sander", "orcid": "0000-0002-9353-6204", "clpid": "Weinreb-S" }, { "family_name": "Emami", "given_name": "Azita", "orcid": "0000-0002-6945-9958", "clpid": "Emami-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Readhead", "given_name": "Anthony C. S.", "orcid": "0000-0001-9152-961X", "clpid": "Readhead-A-C-S" }, { "family_name": "Gaier", "given_name": "Todd C.", "clpid": "Gaier-T-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The field of radio astronomy continues to provide fundamental contributions to the understanding of the evolution, and inner workings of, our universe. It has done so from its humble beginnings, where single antennas and receivers were used for observation, to today's focal plane arrays and interferometers. The number of receiving elements (pixels) in these instruments is quickly growing, currently approaching one hundred. For the instruments of tomorrow, the number of receiving elements will be in the thousands. Such instruments will enable researchers to peer deeper into the fabric of our universe and do so at faster survey speeds. They will provide enormous capability, both for unraveling today's mysteries as well as for the discovery of new phenomena.
\r\n \r\nAmong other challenges, producing the large numbers of low-noise amplifiers required for these instruments will be no easy task. The work described in this thesis advances the state of the art in three critical areas, technological advancements necessary for the future design and manufacturing of thousands of low-noise amplifiers. These areas being: the automated, cryogenic, probing of $\\diameter100$ mm indium phosphide wafers; a system for measuring the noise parameters of devices at cryogenic temperatures; and the development of low-noise, silicon germanium amplifiers for terahertz mixer receivers. The four chapters that comprise the body of this work detail the background, design, assembly, and testing involved in these contributions. Also included is a brief survey of noise parameters, the knowledge of which is fundamental to the design of low-noise amplifiers and the optimization of the system noise temperature for large, dense, interferometers.
", "doi": "10.7907/MW3P-2S22", "publication_date": "2013", "thesis_type": "phd", "thesis_year": "2013" }, { "id": "thesis:7762", "collection": "thesis", "collection_id": "7762", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05282013-164038057", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 19208500, "license": "other", "mime_type": "application/pdf", "url": "/7762/1/thesis.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Electrical and Optical Interconnects for High-Performance Computing", "author": [ { "family_name": "Honarvar Nazari", "given_name": "Meisam", "clpid": "Honarvar-Nazari-Meisam" } ], "thesis_advisor": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" } ], "thesis_committee": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Choo", "given_name": "Hyuck", "clpid": "Choo-Hyuck" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Technology scaling has enabled drastic growth in the computational and storage capacity of integrated circuits (ICs). This constant growth drives an increasing demand for high-bandwidth communication between and within ICs. In this dissertation we focus on low-power solutions that address this demand. We divide communication links into three subcategories depending on the communication distance. Each category has a different set of challenges and requirements and is affected by CMOS technology scaling in a different manner. We start with short-range chip-to-chip links for board-level communication. Next we will discuss board-to-board links, which demand a longer communication range. Finally on-chip links with communication ranges of a few millimeters are discussed.
\r\n\r\nElectrical signaling is a natural choice for chip-to-chip communication due to efficient integration and low cost. IO data rates have increased to the point where electrical signaling is now limited by the channel bandwidth. In order to achieve multi-Gb/s data rates, complex designs that equalize the channel are necessary. In addition, a high level of parallelism is central to sustaining bandwidth growth. Decision feedback equalization (DFE) is one of the most commonly employed techniques to overcome the limited bandwidth problem of the electrical channels. A linear and low-power summer is the central block of a DFE. Conventional approaches employ current-mode techniques to implement the summer, which require high power consumption. In order to achieve low-power operation we propose performing the summation in the charge domain. This approach enables a low-power and compact realization of the DFE as well as crosstalk cancellation. A prototype receiver was fabricated in 45nm SOI CMOS to validate the functionality of the proposed technique and was tested over channels with different levels of loss and coupling. Measurement results show that the receiver can equalize channels with maximum 21dB loss while consuming about 7.5mW from a 1.2V supply. We also introduce a compact, low-power transmitter employing passive equalization. The efficacy of the proposed technique is demonstrated through implementation of a prototype in 65nm CMOS. The design achieves up to 20Gb/s data rate while consuming less than 10mW.
\r\n \r\nAn alternative to electrical signaling is to employ optical signaling for chip-to-chip interconnections, which offers low channel loss and cross-talk while providing high communication bandwidth. In this work we demonstrate the possibility of building compact and low-power optical receivers. A novel RC front-end is proposed that combines dynamic offset modulation and double-sampling techniques to eliminate the need for a short time constant at the input of the receiver. Unlike conventional designs, this receiver does not require a high-gain stage that runs at the data rate, making it suitable for low-power implementations. In addition, it allows time-division multiplexing to support very high data rates. A prototype was implemented in 65nm CMOS and achieved up to 24Gb/s with less than 0.4pJ/b power efficiency per channel. As the proposed design mainly employs digital blocks, it benefits greatly from technology scaling in terms of power and area saving.
\r\n\r\nAs the technology scales, the number of transistors on the chip grows. This necessitates a corresponding increase in the bandwidth of the on-chip wires. In this dissertation, we take a close look at wire scaling and investigate its effect on wire performance metrics. We explore a novel on-chip communication link based on a double-sampling architecture and dynamic offset modulation technique that enables low power consumption and high data rates while achieving high bandwidth density in 28nm CMOS technology. The functionality of the link is demonstrated using different length minimum-pitch on-chip wires. Measurement results show that the link achieves up to 20Gb/s of data rate (12.5Gb/s/$\\mu$m) with better than 136fJ/b of power efficiency.
", "doi": "10.7907/TSX2-EE48", "publication_date": "2013", "thesis_type": "phd", "thesis_year": "2013" }, { "id": "thesis:7675", "collection": "thesis", "collection_id": "7675", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05082013-113725728", "primary_object_url": { "basename": "loh_rui_yan_matthew_2013_thesis.pdf", "content": "final", "filesize": 9062229, "license": "other", "mime_type": "application/pdf", "url": "/7675/1/loh_rui_yan_matthew_2013_thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Dense, Efficient Chip-to-Chip Communication at the Extremes of Computing", "author": [ { "family_name": "Loh Rui Yan", "given_name": "Matthew", "clpid": "Loh-Rui-Yan-Matthew" } ], "thesis_advisor": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" } ], "thesis_committee": [ { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Tai", "given_name": "Yu-Chong", "clpid": "Tai-Yu-Chong" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The scalability of CMOS technology has driven computation into a diverse range of applications across the power consumption, performance and size spectra. Communication is a necessary adjunct to computation, and whether this is to push data from node-to-node in a high-performance computing cluster or from the receiver of wireless link to a neural stimulator in a biomedical implant, interconnect can take up a significant portion of the overall system power budget. Although a single interconnect methodology cannot address such a broad range of systems efficiently, there are a number of key design concepts that enable good interconnect design in the age of highly-scaled CMOS: an emphasis on highly-digital approaches to solving \u2018analog\u2019 problems, hardware sharing between links as well as between different functions (such as equalization and synchronization) in the same link, and adaptive hardware that changes its operating parameters to mitigate not only variation in the fabrication of the link, but also link conditions that change over time. These concepts are demonstrated through the use of two design examples, at the extremes of the power and performance spectra.
\r\n\r\nA novel all-digital clock and data recovery technique for high-performance, high density interconnect has been developed. Two independently adjustable clock phases are generated from a delay line calibrated to 2 UI. One clock phase is placed in the middle of the eye to recover the data, while the other is swept across the delay line. The samples produced by the two clocks are compared to generate eye information, which is used to determine the best phase for data recovery. The functions of the two clocks are swapped after the data phase is updated; this ping-pong action allows an infinite delay range without the use of a PLL or DLL. The scheme's generalized sampling and retiming architecture is used in a sharing technique that saves power and area in high-density interconnect. The eye information generated is also useful for tuning an adaptive equalizer, circumventing the need for dedicated adaptation hardware.
\r\n\r\nOn the other side of the performance/power spectra, a capacitive proximity interconnect has been developed to support 3D integration of biomedical implants. In order to integrate more functionality while staying within size limits, implant electronics can be embedded onto a foldable parylene (\u2018origami\u2019) substrate. Many of the ICs in an origami implant will be placed face-to-face with each other, so wireless proximity interconnect can be used to increase communication density while decreasing implant size, as well as facilitate a modular approach to implant design, where pre-fabricated parylene-and-IC modules are assembled together on-demand to make custom implants. Such an interconnect needs to be able to sense and adapt to changes in alignment. The proposed array uses a TDC-like structure to realize both communication and alignment sensing within the same set of plates, increasing communication density and eliminating the need to infer link quality from a separate alignment block. In order to distinguish the communication plates from the nearby ground plane, a stimulus is applied to the transmitter plate, which is rectified at the receiver to bias a delay generation block. This delay is in turn converted into a digital word using a TDC, providing alignment information.
\r\n", "doi": "10.7907/FQ18-2X96", "publication_date": "2013", "thesis_type": "phd", "thesis_year": "2013" }, { "id": "thesis:6765", "collection": "thesis", "collection_id": "6765", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:01082012-184435123", "primary_object_url": { "basename": "Bohn_Thesis_edit2_export.pdf", "content": "final", "filesize": 4637504, "license": "other", "mime_type": "application/pdf", "url": "/6765/1/Bohn_Thesis_edit2_export.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Integrated Circuit Signal Generation and Detection Techniques for Microwave and Sub-Millimeter Wave Signals", "author": [ { "family_name": "Bohn", "given_name": "Florian", "clpid": "Bohn-Florian" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Chattopadhyay", "given_name": "Goutam", "clpid": "Chattopadhyay-G" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The unabated reduction of device feature sizes in semiconductor processes, particularly in complementary metal-oxide semiconductor (CMOS) processes, has served as the enabling factor behind integrated electronic systems of ever increasing complexity and speeds. As a result, former niche market applications, such as the global-positioning system (GPS), cellular telephony or powerful general purpose computers, have expanded into the field of consumer electronics with tremendous impact on the daily lives of millions of people. It is, therefore, only logical that the future will bring new applications to the mass market that today only exist as niche applications.\r\nSystems operating in the millimeter wave frequency range are an example of a current niche market, with current research striving to fully integrate such systems using advanced semiconductor processing technology. Electromagnetic waves at these frequencies become comparable in size to the electronics circuits. This opens the possibility for novel design approaches that were traditionally not available to integrated circuit radio-frequency designers. On the other hand, the increase in the number of available devices also brings with it new challenges due to increasing variability in device performance. Self-correcting techniques for integrated circuits that offset this increased variability are therefore also highly desirable.
\r\n\r\nIn this dissertation, we explore the above issues on several fronts. We will first present a phase-locked loop synthesizer that auto-corrects its spurious output tones as an example of circuits that correct for a parasitic effect by leveraging the availability of many active devices to construct a digital feedback loop. We will then focus on the effort to operate CMOS integrated circuits in the terahertz regime by developing a solid design foundation for converting signals to frequencies beyond the maximum power gain frequency\u3016 f\u3017_max. We will use the insights gained to develop and explore two designs generating power at these high frequencies as proofs of concept. Finally, we will focus on the passive electromagnetic components of such high frequency systems and present a novel way of designing electromagnetic structures that are comparable to the wavelength size in integrated systems by introducing the third physical dimension into the design process for integrated electromagnetic structures.
\r\n", "doi": "10.7907/Q018-QP18", "publication_date": "2012", "thesis_type": "phd", "thesis_year": "2012" }, { "id": "thesis:7161", "collection": "thesis", "collection_id": "7161", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06122012-091920562", "type": "thesis", "title": "Superconducting Microwave Resonator Arrays for Submillimeter/Far-infrared Imaging", "author": [ { "family_name": "Noroozian", "given_name": "Omid", "clpid": "Noroozian-Omid" } ], "thesis_advisor": [ { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" } ], "thesis_committee": [ { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "local_group": [ { "literal": "Caltech Submillimeter Observatory" }, { "literal": "Astronomy Department" }, { "literal": "div_eng" } ], "abstract": "Superconducting microwave resonators have the potential to revolutionize submillimeter and far-infrared astronomy, and with it our understanding of the universe. The field of low-temperature detector technology has reached a point where extremely sensitive devices like transition-edge sensors are now capable of detecting radiation limited by the background noise of the universe. However, the size of these detector arrays are limited to only a few thousand pixels. This is because of the cost and complexity of fabricating large-scale arrays of these detectors that can reach up to 10 lithographic levels on chip, and the complicated SQUID-based multiplexing circuitry and wiring for readout of each detector. In order to make substantial progress, next- generation ground-based telescopes such as CCAT or future space telescopes require focal planes with large-scale detector arrays of 104\u2013106 pixels. Arrays using microwave kinetic inductance detectors (MKID) are a potential solution. These arrays can be easily made with a single layer of superconducting metal film deposited on a silicon substrate and pattered using conventional optical lithography. Furthermore, MKIDs are inherently multiplexable in the frequency domain, allowing \u223c 103 detectors to be read out using a single coaxial transmission line and cryogenic amplifier, drastically reducing cost and complexity.
\r\n\r\nAn MKID uses the change in the microwave surface impedance of a superconducting thin-film microresonator to detect photons. Absorption of photons in the superconductor breaks Cooper pairs into quasiparticles, changing the complex surface impedance, which results in a perturbation of resonator frequency and quality factor. For excitation and readout, the resonator is weakly coupled to a transmission line. The complex amplitude of a microwave probe signal tuned on-resonance and transmitted on the feedline past the resonator is perturbed as photons are absorbed in the superconductor. The perturbation can be detected using a cryogenic amplifier and subsequent homodyne mixing at room temperature. In an array of MKIDs, all the resonators are coupled to a shared feedline and are tuned to slightly different frequencies. They can be read out simultaneously using a comb of frequencies generated\r\nand measured using digital techniques.
\r\n\r\nThis thesis documents an effort to demonstrate the basic operation of \u223c 256 pixel arrays of lumped-element MKIDs made from superconducting TiNx on silicon. The resonators are designed and simulated for optimum operation. Various properties of the resonators and arrays are measured and compared to theoretical expectations. A particularly exciting observation is the extremely high quality factors (\u223c 3 \u00d7 107) of our TiNx resonators which is essential for ultra-high sensitivity. The arrays are tightly packed both in space and in frequency which is desirable for larger full-size arrays. However, this can cause a serious problem in terms of microwave crosstalk between neighboring pixels. We show that by properly designing the resonator geometry, crosstalk can be eliminated; this is supported by our measurement results. We also tackle the problem of excess frequency noise in MKIDs. Intrinsic noise in the form of an excess resonance frequency jitter exists in planar superconducting resonators that are made on dielectric substrates. We conclusively show that this noise is due to fluctuations of the resonator capacitance. In turn, the capacitance fluctuations are thought to be driven by two-level system (TLS) fluctuators in a thin layer on the surface of the device. With a modified resonator design we demonstrate with measurements that this noise can be substantially reduced. An optimized version of this resonator was designed for the multiwavelength submillimeter kinetic inductance camera (MUSIC) instrument for the Caltech Submillimeter Observatory.
", "doi": "10.7907/8MG2-NB23", "publication_date": "2012", "thesis_type": "phd", "thesis_year": "2012" }, { "id": "thesis:6434", "collection": "thesis", "collection_id": "6434", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05252011-110433288", "primary_object_url": { "basename": "Perkins_thesis_complete.pdf", "content": "", "filesize": 6767057, "license": "other", "mime_type": "application/pdf", "url": "/6434/1/Perkins_thesis_complete.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Experimental and Analytical Studies of Merging Plasma Loops on the Caltech Solar Loop Experiment", "author": [ { "family_name": "Perkins", "given_name": "Rory James", "clpid": "Perkins-Rory-James" } ], "thesis_advisor": [ { "family_name": "Bellan", "given_name": "Paul Murray", "clpid": "Bellan-P-M" } ], "thesis_committee": [ { "family_name": "Bellan", "given_name": "Paul Murray", "clpid": "Bellan-P-M" }, { "family_name": "Polk", "given_name": "James E.", "clpid": "Polk-J-E" }, { "family_name": "Ott", "given_name": "Christian D.", "clpid": "Ott-C-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "Of crucial importance for magnetized plasmas is magnetic helicity, a topological quantity that measures the knottedness or twistedness of the magnetic field. A universal relaxation theory, applicable to astrophysical and laboratory plasmas, dictates the evolution of plasmas towards an equilibrium state based solely on helicity content. The Caltech Solar Loop Experiment creates plasma with injected helicity to study this evolution, which can involve the merging of two plasma loops into a single structure. This thesis studies the merging using two techniques. The first is the construction of an array of vacuum photodiodes to measure extreme ultraviolet radiation from the experiment; the data provides information concerning non-equilibrium radiation losses and magnetic reconnection. The second is a Hamiltonian study of particle orbits to explain how particles can transition from being localized from one plasma loop to being shared among two neighboring loops. This shows how the merging process may initiate and also leads to a general theorem where the action variable serves as a Hamiltonian for the orbit-averaged system.", "doi": "10.7907/Z1PS-YB20", "publication_date": "2011", "thesis_type": "phd", "thesis_year": "2011" }, { "id": "thesis:6005", "collection": "thesis", "collection_id": "6005", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:08232010-071647727", "type": "thesis", "title": "Techniques for Mixed-Signal Linearization and Large Signal Handling in Radio-Frequency Receiver Circuits", "author": [ { "family_name": "Keehr", "given_name": "Edward Arthur", "clpid": "Keehr-Edward-Arthur" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hassibi", "given_name": "Babak", "clpid": "Hassibi-B" }, { "family_name": "D'Addario", "given_name": "Larry R.", "clpid": "D'Addario-L-R" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "In this dissertation, two effective linearization schemes for radio-frequency receivers are introduced. The first of these comprises a mixed-signal feedforward path which regenerates third-order intermodulation (IM3) products at radio frequencies, downconverts these products, digitizes them, and then uses them to cancel corruptive IM3 products in the digital baseband portion of a nominally linear receiver path. The combined implemented receiver represents a SAW-less direct-conversion receiver for UMTS FDD Region 1 that achieves an uncorrected out-of-band IIP3 of -7.1dBm under worst-case blocking specifications. Under IM3 equalization, the receiver achieves an effective IIP3 of +5.3dBm and meets the UMTS BER sensitivity requirements with 3.7dB of margin. To enable this mixed-signal feedforward path, a multistage cubic term generator is introduced which uses cascaded nonlinear operations to generate reference IM3 products. The multistage nature of this circuit is considered in the context of the aforementioned linearization scheme and is shown to provide sufficient dynamic range for nearly complete IM3 cancellation while dissipating far less power than the original receiver front end. In particular, the effect of the group delay between stages is analyzed and shown to permit large IM3 cancellation ratios for interstage group delays less than 1ns.
\r\n\r\nExpanding upon the first effective linearization approach led to the development of a large signal handling receiver with an out-of-band 1-dB desensitization point of +12.5dBm. Enabling this large signal handling capability is a passive mixer downconverter preceded by a novel wide-swing LNTA. With a stacked push-pull class-AB common-gate architecture, the LNTA reduces the magnitude of input-referred distortion by up to 40dB beyond that predicted by an initial slope-of-3 characteristic while at the same time minimally impacting the effective small-signal gain of the receiver. To compensate for intermodulation distortion terms of order greater than 3, IM3 and IM2 products are processed down to digital baseband where they are successively multiplied to generate approximations to higher-order terms. In the case of a +12.4dBm QPSK-modulated signal and a -16.3dBm CW blocker, cancellation improves receiver input-referred error by over 24dB, resulting in an extrapolated IIP3 of +43.5dBm.
", "doi": "10.7907/WFGT-4823", "publication_date": "2011", "thesis_type": "phd", "thesis_year": "2011" }, { "id": "thesis:6281", "collection": "thesis", "collection_id": "6281", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04082011-064907780", "primary_object_url": { "basename": "HSIEH_PhD_thesis_2011.pdf", "content": "final", "filesize": 5320736, "license": "other", "mime_type": "application/pdf", "url": "/6281/1/HSIEH_PhD_thesis_2011.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Imaging with Second-Harmonic Generation Nanoparticles", "author": [ { "family_name": "Hsieh", "given_name": "Chia-Lung", "clpid": "Hsieh-Chia-Lung" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Perona", "given_name": "Pietro", "clpid": "Perona-P" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" }, { "family_name": "Daraio", "given_name": "Chiara", "clpid": "Daraio-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Second-harmonic generation nanoparticles show promise as imaging probes due to their coherent and stable signal with a broad flexibility in the choice of excitation wavelength. In this thesis, we developed and demonstrated barium titanate nanoparticles as second-harmonic radiation imaging probes. We studied the absolute second-harmonic generation efficiency of the nanoparticles on single-particle level. The polarization dependent second-harmonic signal of single nanoparticles was studied in detail. From the measured polar response, we were able to find the orientation of the nanoparticle. We developed a biochemical interface for using the second-harmonic nanoprobes as biomarkers, including in vitro cellular imaging and in vivo live animal imaging. The nanoparticles were surface functionalized with primary amine groups for stable colloidal dispersion. We achieved specific labeling of the second-harmonic nanoprobes via immunostaining where the antibodies were covalently conjugated onto the nanoparticles. We observed no toxicity of the functionalized nanoparticles to biological cells. The coherent second-harmonic signal radiated from the nanoparticles offers opportunities for new imaging techniques. Using interferometric detection, namely harmonic holography, both amplitude and phase of the second-harmonic field can be captured. Through digital beam propagation, three-dimensional field distribution, reflecting three-dimensional distribution of the nanoparticles, can be reconstructed. We achieved a scan-free three-dimensional imaging of nanoparticles in biological cells with sub-micron spatial resolution by using the harmonic holographic microscope. We further exploited the coherent second-harmonic signal for imaging through scattering media by performing optical phase conjugation of the second-harmonic signal. We demonstrated an all-digital optical phase conjugation of the second-harmonic signal originated from a nanoparticle by combining harmonic holography and dynamic computer generated holography using a spatial light modulator. The phase-conjugated second-harmonic scattered field retraced the scattering trajectory and formed a clean focus on the nanoparticle placed inside a scattering medium. The nanoparticle acted as a beacon of light; it helped us find the tailored wavefront for concentrating light at the nanoparticle inside the scattering medium. We also demonstrated imaging through a thin scattering medium by raster-scanning the phase-conjugated focus in the vicinity of the beacon nanoparticle, in which a clear image of a target placed behind a ground glass diffuser was obtained.", "doi": "10.7907/WCS2-FD82", "publication_date": "2011", "thesis_type": "phd", "thesis_year": "2011" }, { "id": "thesis:5295", "collection": "thesis", "collection_id": "5295", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10122009-094525715", "type": "thesis", "title": "Instrumentation for Wide Bandwidth Radio Astronomy", "author": [ { "family_name": "Jones", "given_name": "Glenn Evans", "clpid": "Jones-Glenn-Evans" } ], "thesis_advisor": [ { "family_name": "Weinreb", "given_name": "Sander", "orcid": "0000-0002-9353-6204", "clpid": "Weinreb-S" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Weinreb", "given_name": "Sander", "orcid": "0000-0002-9353-6204", "clpid": "Weinreb-S" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "orcid": "0000-0003-3003-7042", "clpid": "Vaidyanathan-P-P" }, { "family_name": "Readhead", "given_name": "Anthony C. S.", "orcid": "0000-0001-9152-961X", "clpid": "Readhead-A-C-S" }, { "family_name": "Kuiper", "given_name": "Thomas B. H.", "clpid": "Kuiper-T-B-H" }, { "family_name": "Jarnot", "given_name": "Robert F.", "clpid": "Jarnot-R-F" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Centimeter wavelength radio astronomy spans approximately two decades in frequency, from roughly 500 MHz to 50 GHz. In contrast, radio astronomy instruments have traditionally been limited to at most octave bandwidths, necessitating multiple instruments on a given telescope to cover a large fraction of the spectrum. This paradigm is infeasible for the next generation of telescopes, which will likely consist of hundreds to thousands of small dishes combined together in an array, because each receiver must be replicated for each element in the array. Therefore, wide bandwidth instrumentation must be developed for radio astronomy.
\r\n\r\nThis thesis presents a novel radio telescope with excellent system noise temperature and reasonable efficiency across an instantaneous fractional bandwidth greater than 4:1; amongst the widest ever demonstrated. This instrument illustrates that extremely wide bandwidth instruments are feasible, even in the presence of terrestrial interference. To make use of the enormous instantaneous bandwidth, a flexible, high performance, and cost effective digital signal processing system is also presented. Theory, design, and measurements of special purpose digital spectrometers built to minimize the effects of terrestrial interference are included.
\r\n\r\nAside from the practical advantages offered by wide bandwidth instrumentation, new scientific applications are also made possible. A special purpose system for performing detailed studies of giant radio pulses from rotating neutron stars (pulsars) is presented, along with demonstrations including some of the largest fractional bandwidth observations of these pulses made to date. This system includes a sensitive trigger which corrects for the dispersive effects of the interstellar medium in real time and a deep capture buffer optimized for observing repetitive transient phenomena. Measurements made using the trigger system at Arecibo Observatory are also presented to demonstrate the portability of the instrument.
", "doi": "10.7907/BMZR-P813", "publication_date": "2010", "thesis_type": "phd", "thesis_year": "2010" }, { "id": "thesis:1684", "collection": "thesis", "collection_id": "1684", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05082009-143935", "primary_object_url": { "basename": "Thesis_Motofumi_Arii.pdf", "content": "final", "filesize": 10337702, "license": "other", "mime_type": "application/pdf", "url": "/1684/1/Thesis_Motofumi_Arii.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Retrieval of Soil Moisture under Vegetation Using Polarimetric Radar", "author": [ { "family_name": "Arii", "given_name": "Motofumi", "orcid": "0000-0002-3242-7987", "clpid": "Arii-Motofumi" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "van Zyl", "given_name": "Jakob J.", "clpid": "van-Zyl-J-J" }, { "family_name": "Kim", "given_name": "Yunjin", "clpid": "Kim-Yunjin" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Elachi", "given_name": "Charles", "clpid": "Elachi-C" }, { "family_name": "van Zyl", "given_name": "Jakob J.", "clpid": "van-Zyl-J-J" }, { "family_name": "Kim", "given_name": "Yunjin", "clpid": "Kim-Yunjin" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The unique contributions of this thesis are: 1) a polarimetric classification algorithm that is a significant improvement over an existing algorithm and 2) introduction of a cube technique to retrieve soil moisture under vegetation.
\r\n\r\nThe most widely used classification algorithm is the three-component scattering technique. Even though it includes three dominant scattering mechanisms, the decomposition approach can cause a non-physical solution due to incorrect assumptions. The Adaptive Non Negative Eigenvalue Decomposition approach in this thesis produces correct solution. It appears that this new approach provides better classification results. It is a significant improvement over the existing technique.
\r\n\r\nA cube technique is introduced to retrieve soil moisture under vegetation. Using this approach, we have evaluated the retrieval accuracy of several polarimetric combinations. The effects of the incorrect vegetation model and data noise were investigated. In addition, the proposed cube algorithm can be improved by applying the classification result.
\r\n", "doi": "10.7907/SKJ9-KT40", "publication_date": "2009", "thesis_type": "phd", "thesis_year": "2009" }, { "id": "thesis:5179", "collection": "thesis", "collection_id": "5179", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03292009-070752", "primary_object_url": { "basename": "Thesis-yujiu-final-20090331.pdf", "content": "final", "filesize": 3325286, "license": "other", "mime_type": "application/pdf", "url": "/5179/1/Thesis-yujiu-final-20090331.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Circuits and Systems for Wireless Concurrent Communication", "author": [ { "family_name": "Wang", "given_name": "Yu-Jiu", "orcid": "0000-0002-2534-1069", "clpid": "Wang-Yu-Jiu" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Concurrency is a special kind of analog circuit parallelism that uses a single circuit with necessary bandwidth to process multiple signals at the same time. Concurrent radios offer a higher data rate and improved system diversity. Our comprehensive treatment comprises proposals for potential transceiver architectures, invention of circuit blocks, and provisions of innovative analysis methods.
\r\n\r\nThe analysis of concurrent circuits are often complex. To simplify noise analysis, a R^(N^2 )-vector space is first proposed to re-formulate the N-port network noise modeling problem. Any internal physical source inside the noisy network contributes a small vector in the defined R^(N^2)-vector space, and the aggregate statistical behavior of this noisy network can be viewed as the vector sum of these vectors. Applying this concept to FET noise modeling leads to several modified FET noise models, in which three uncorrelated noise sources are sufficient to describe the statistical behavior of an intrinsic FET. The use of these new FET models can simplify the analysis, simulation, and optimization of low noise systems without sacrificing accuracy.
\r\n\r\nBroadband low-noise amplifier is a critical block in concurrent receiver systems. We propose a novel low-noise weighted distributed amplifier (WDA) topology, which uses the internal finite-impulse-response filtering inside a conventional distributed amplifier to partially suppress internal thermal noise. A distinct advantage of this topology is its tolerance to input parasitic capacitance which can be used to provide good electro-static discharge (ESD) protection without sacrificing its noise performance and power consumption. A compact 3.1\u250010.6 GHz WDA IC is built on a 130 nm CMOS process. Experimental results show 2.3\u25004.5 dB NF at 23 mW power consumption.
\r\n\r\nUsing concurrency in wireless link can boost communication data rate. As a proof-of concept, we propose dynamically scalable concurrent communication by dividing the 7.5 GHz bandwidth of the unlicensed 3.1\u250010.6 GHz spectrum into seven concurrent channels. A CMOS octa-core RF receiver is implemented to validate the idea. Based on the receiver measurement results, a wireless link can be built to achieve a 16 Gbps channel limit at five meter TX-RX distance at 400 mW power consumption.
\r\n\r\nTunable concurrency can improve the receiver diversity. A prototype 6\u250018 GHz concurrent tunable dual-band phased array receiver element IC is proposed and built on a 130 nm CMOS process. Experimental results demonstrate successful dual-band RF reception within a low band (6\u250010.4 GHz) and high band (10.4\u250018 GHz) with 300 MHz baseband bandwidth. A final four-element phased array receiver built from the prototyped ICs shows an array pattern with worst-case 21 dB peak-to-null ratio across all frequencies.
\r\n\r\nConcurrency can also be used to achieve multi-beam reception by providing multiple phase-shifts for each RF signals and combining them separately at baseband outputs. A 10.4\u250018 GHz concurrent dual-beam phased array receiver is proposed based on this concept, and is implemented on a 130 nm CMOS process. A final four-element phased array system shows successful concurrent dual-beam reception at the same RF frequency.
Yu-Jiu Wang (209\r\n", "doi": "10.7907/FZ1R-MJ30", "publication_date": "2009", "thesis_type": "phd", "thesis_year": "2009" }, { "id": "thesis:2531", "collection": "thesis", "collection_id": "2531", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06092009-113849", "primary_object_url": { "basename": "Bardin_thesis_final.PDF", "content": "final", "filesize": 7572900, "license": "other", "mime_type": "application/pdf", "url": "/2531/1/Bardin_thesis_final.PDF", "version": "v2.0.0" }, "type": "thesis", "title": "Silicon-Germanium Heterojunction Bipolar Transistors for Extremely Low-Noise Applications", "author": [ { "family_name": "Bardin", "given_name": "Joseph Cheney", "orcid": "0000-0002-6523-6730", "clpid": "Bardin-Joseph-Cheney" } ], "thesis_advisor": [ { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Historically speaking, the world of extremely low-noise solid-state amplification has been dominated by exotic technologies such as InP and GaAs HEMTs. By cryogenically cooling these devices, it is possible to realize microwave amplifiers with noise temperatures as low as 5K over decades of bandwidth. Although HEMTs can provide very low noise amplification when cooled to cryogenic temperatures, their radiometer performance is limited by intrinsic transconductance fluctuations. It is believed that bipolar devices do not suffer from this problem. As industry has invested more and more money into silicon based technologies, silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) have continued to improve and are now at the point where they are beginning to become competitive with InP HEMTs for microwave cryogenic low-noise amplifiers. Although extremely high frequency device operation has been observed at cryogenic temperatures, little work has been done on modeling the noise of cooled SiGe HBTs.
\r\n\r\nIn this report, a thorough investigation into the theoretical and practical aspects of using silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) for extremely low-noise applications is presented. The dissertation is broken up into three sections:
\r\n\r\n1) Background information: The fundamentals of SiGe HBTs are presented along with a discussion of how the properties of semiconductors change at cryogenic temperatures, as well the impact that these changes have on the performance of the devices.
\r\n\r\n2) Modeling: A comprehensive study of seven state-of-the-art HBTs at temperatures ranging from 18 K to 300 K is presented. The devices are compared in terms of dc, small-signal, and noise performance, and small-signal noise models are extracted. The section concludes with a brief summary of the important conclusions regarding the performance of SiGe devices at cryogenic temperatures.
\r\n\r\n3) Applications: The models developed previously are applied to the design of several state-of-the-art LNAs in both MMIC and discrete form. Noise performance better than 2 K is achieved in the low-GHz range, which is comparable to the best InP results. The section concludes with a discussion of some high-impedance differential amplifiers which have recently been fabricated.
\r\n", "doi": "10.7907/MCPE-4M30", "publication_date": "2009", "thesis_type": "phd", "thesis_year": "2009" }, { "id": "thesis:5227", "collection": "thesis", "collection_id": "5227", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06082008-174204", "primary_object_url": { "basename": "AydinBabakhaniThesis.pdf", "content": "final", "filesize": 7140526, "license": "other", "mime_type": "application/pdf", "url": "/5227/1/AydinBabakhaniThesis.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Direct Antenna Modulation (DAM) for On-Chip mm-Wave Transceivers", "author": [ { "family_name": "Babakhani", "given_name": "Aydin", "orcid": "0000-0001-8123-9061", "clpid": "Babakhani-Aydin" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Emami", "given_name": "Azita", "clpid": "Emami-A" }, { "family_name": "Hassibi", "given_name": "Babak", "clpid": "Hassibi-B" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "In the last few decades the puissant desire to miniaturize the digital circuits to achieve higher speed and larger density has shaped the evolution of the silicon-based technologies. This development opens a new era in the field of millimeter-wave electronics in which many low-cost high-yield silicon-based transistors can be used on a single chip to enable creation of novel architectures with unique properties not achievable with old processes. In addition to this high level of integration capability, the die size of comparable or even larger than the wave-length makes it possible to integrate antennas, transceivers, and digital circuitry all on a single silicon die.
\r\n\r\nIt is important to realize that although smaller parasitic capacitors and shorter transistor channels have improved fT and fmax of transistors, extremely thin metal layers, highly doped substrates, and low breakdown voltage transistors have severely affected the performance of analog and RF building blocks. For example, thin metal layers have increased the loss and lowered the quality factor of the building blocks such as capacitors and inductors and low breakdown voltage transistors have made the power generation quite challenging. Additionally, if not carefully designed, small wave-lengths in the millimeter-wave range may cause unintended radiation by on-chip components. In this dissertation, we address these issues in design of millimeter-wave silicon-based single-chip phased-array transceivers with integrated antennas. We also introduce the technique of Direct Antenna Modulation (DAM) and implement two proof-of-concept chips operating at 60 GHz.
\r\n\r\nWe will present the receiver and the on-chip antenna sections of a fully integrated 77 GHz four-element phased-array transceiver with on-chip antennas in silicon. The receiver section of the chip includes the complete down-conversion path comprising low-noise amplifier (LNA), frequency synthesizer, phase rotators, combining amplifiers, and on-chip dipole antennas. The signal combining is performed using a novel distributed active combining amplifier at an IF of 26 GHz. In the LO path, the output of the 52 GHz VCO is routed to different elements and can be phase shifted locally by the phase rotators. A silicon lens on the backside is used to reduce the loss due to the surface-wave power of the silicon substrate. Our measurements show a single-element LNA gain of 23 dB and a noise figure of 6.0 dB. Each of the four receive paths has a gain of 37 dB and a noise figure of 8.0 dB. Each on-chip antenna has a gain of +8 dBi.
\r\n\r\nA direct antenna modulation (DAM) technique is also introduced, where the radiated far-field signal is modulated by time-varying changes in the antenna near-field electromagnetic (EM) boundary conditions. This enables the transmitter to send data in a direction-dependent fashion producing a secure communication link. The transmitter architecture makes it possible to use narrow-band highly-efficient switching power amplifiers to transmit wideband constant and non-constant envelope modulated signals. Theoretically, these systems are capable of transmitting independent data in multiple directions at full-rate concurrently using a single transmitter. Direct antenna modulation (DAM) can be performed by using either switches or varactors. Two proof-of-concept DAM transmitters operating at 60GHz using switches and varactors are demonstrated in silicon proving the feasibility of this approach.
", "doi": "10.7907/BS6T-1S20", "publication_date": "2008", "thesis_type": "phd", "thesis_year": "2008" }, { "id": "thesis:1663", "collection": "thesis", "collection_id": "1663", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05072008-075138", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 7671079, "license": "other", "mime_type": "application/pdf", "url": "/1663/1/thesis.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Submillimeter Wave Camera Using A Novel Photon Detector Technology", "author": [ { "family_name": "Kumar", "given_name": "Shwetank", "clpid": "Kumar-Shwetank" } ], "thesis_advisor": [ { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "Bockrath", "given_name": "Marc William", "clpid": "Bockrath-M-W" } ], "local_group": [ { "literal": "Caltech Submillimeter Observatory" }, { "literal": "Astronomy Department" }, { "literal": "div_eng" } ], "abstract": "Cryogenic photon detectors can be used to make extremely sensitive cameras for submillimeter astronomy. Current detector technologies already have sensitivities limited by the noise due to photon arrival statistics. To further improve the sensitivity and mapping speed of experiments for a wide field survey, focal planes containing tens of thousands of pixels are required. Unfortunately, the current technologies use discrete and massive components which are not easy to integrate into large arrays. This thesis presents a 16-pixel, two-color, submillimeter-wave, prototype camera developed at Caltech and the Jet Propulsion Laboratory using a novel photon detector technology. The camera also uses new designs for other constituent elements \u2013 the antenna, transmission line feednetwork, and bandpass filters \u2013 to implement the sub-millimeter pixels. These designs allow integration of the entire camera onto a single chip and conclusively address the problem of scalability while maintaining the sensitivity and noise performance of the current technologies. This thesis explains the design of each of these components and presents the results from experiments conducted to test their performance. Results from the 'first light', obtained by mounting the prototype camera onto the Caltech Submillimeter Observatory (CSO), are also presented.
\r\n\r\nWe have also studied the temperature and power dependence of the resonance frequency, quality factor, and frequency noise of the superconducting niobium thin-film coplanar waveguide (CPW) resonators in order to understand the factors affecting the noise performance of our photon detectors. These experiments were carried out at temperatures well below the superconducting transition (Tc = 9.2 K) in an attempt to understand the source of the excess frequency noise of superconducting resonators which form the sensing element of our photon detectors. The noise decreases by nearly two orders of magnitude as the temperature is increased from 120 to 1200 mK, while the variation of the resonance frequency with temperature over this range agrees well with the standard two-level systems (TLS) model for amorphous dielectrics. These results support the hypothesis that TLS are responsible for the noise in superconducting microresonators and have important implications for resonator applications such as qubits and photon detectors.
\r\n", "doi": "10.7907/F58T-SV45", "publication_date": "2008", "thesis_type": "phd", "thesis_year": "2008" }, { "id": "thesis:3011", "collection": "thesis", "collection_id": "3011", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08042006-144107", "primary_object_url": { "basename": "Thesis_Ehsan.pdf", "content": "final", "filesize": 30587538, "license": "other", "mime_type": "application/pdf", "url": "/3011/1/Thesis_Ehsan.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Optotronics: Optically Inspired Electronics", "author": [ { "family_name": "Afshari", "given_name": "Ehsan", "orcid": "0000-0002-4528-1788", "clpid": "Afshari-Ehsan" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Marsden", "given_name": "Jerrold E.", "clpid": "Marsden-J-E" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Waves are everywhere, from the distribution of cars on a highway to the wave patterns in the ocean. Intriguing phenomena in wave propagation, such as Soliton resonance, kink-antikink interaction, self-focusing, and Peakon generation can be used in many practical applications leading to novel architectures for signal processing and generation. These E/M based approaches could be particularly useful in the case of Extremely Wide Band (EWB) (DC to more than 100GHz) circuits and systems where the limited transistor cut-off frequency, maximum power efficiency, and breakdown voltage pose serious constraints on the use of conventional circuit techniques.
\r\n\r\nTo overcome the limitations of active devices in EWB signal processing and generation, we propose a general class of solutions based on novel circuit topologies inspired by commonly used structures in electromagnetics, and more specifically optics. The proposed methodology is based on nonlinear and/or inhomogeneous one-dimensional (1D) transmission lines which we have successfully extended to two-dimensional transmission lattices. The principles behind these designs stem from the mathematical theory of linear and nonlinear wave propagation. By analyzing the models for the transmission lines/lattices, we are able to exploit the large body of theory to design circuits, demonstrating the narrowest reported pulse on silicon (2.5ps), and for a single integrated-circuit silicon-based amplifier, the highest achieved center frequency of operation (85GHz) and the highest achieved power output (120mW) at this frequency. In addition, we have reported the first in-silicon transmission line system capable of sharpening both rising and falling edges of NRZ data by increasing the bandwidth. In the end, we will also present how the same approach can be applied to realize ultra-fast computation systems (such as a sub-nanosecond Fourier and Hankel transformers in silicon) and other structures, leading to a new design discipline we like to call \"Optotronics\".
\r\n", "doi": "10.7907/Z95M63XK", "publication_date": "2007", "thesis_type": "phd", "thesis_year": "2007" }, { "id": "thesis:2367", "collection": "thesis", "collection_id": "2367", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06012007-130844", "primary_object_url": { "basename": "Arun_Natarajan_Thesis.pdf", "content": "final", "filesize": 42998359, "license": "other", "mime_type": "application/pdf", "url": "/2367/1/Arun_Natarajan_Thesis.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Millimeter-Wave Phased Arrays in Silicon", "author": [ { "family_name": "Natarajan", "given_name": "Arun Sridhar", "clpid": "Natarajan-Arun-Sridhar" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "D'Addario", "given_name": "Larry R.", "clpid": "D'Addario-L-R" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Integration of mm-wave multiple-antenna systems on silicon-based processes enables complex, low-cost systems for high-frequency communication and sensing applications. While individual silicon devices struggle to achieve the same performance as III-V semiconductor-based transistors at mm-wave frequencies, the benefits of integration, such as good component matching and near-zero incremental device cost, can be leveraged to achieve good system performance. This dissertation presents different techniques and architectures for integrating mm-wave phased arrays on commercial silicon process technologies by demonstrating phased-array transmitters and receivers at 24GHz, 60GHz, and 77GHz, in CMOS and SiGe BiCMOS processes.
\r\n\r\nInitially, the tradeoffs of high-frequency systems are discussed in the context of Shannon capacity and the benefits of integrating phased arrays at such high frequencies are discussed in detail. An analysis of the output noise in a phased-array receiver in the presence of antenna coupling and input noise correlation is carried out and measurements on a discrete two-element array demonstrate the dependence of output noise on the phase-shift setting.
\r\n\r\nThe design of the first fully-integrated 24GHz phased-array transmitter using mainly 0.18[mu]m CMOS transistors is described. The four-element array adopts a centralized LO-path phase-shifting approach using a multi-phase VCO. The on-chip 19.2GHz VCO generates 16 equally spaced LO phases leading to 7 degree beam resolution for radiation normal to the array. The transmitter includes four on-chip CMOS power amplifiers, with outputs matched to 50 Ohms, that are each capable of generating up to 14.5dBm of output power at 24GHz. The array achieves a peak-to-null ratio of 23dB with four elements active and can support data rates of 500Mb/s on each channel (with BPSK modulation) while occupying 6.8mm x 2.1mm of die area.
\r\n\r\nA high-resolution local LO-path phase-shifting architecture is presented as part of the first fully-integrated 77GHz phased-array transceiver in a SiGe BiCMOS process. The SiGe transceiver includes four transmit and four receive elements (including 77GHz LNA and PA), along with the LO frequency generation and distribution circuitry. The local LO-path phase-shifting scheme enables a robust distribution network that scales well with increasing frequency and/or number of elements, while providing high-resolution phase shifts. Each transmit element of the heterodyne transmitter generates +12.5dBm of output power at 77GHz, with a bandwidth of 2.5GHz leading to a four-element EIRP of 24.5dBm. Each on-chip PA has a maximum saturated power of +17.5dBm at 77GHz while the on-chip VCO achieves a phase noise of -95dBc/Hz@1MHz offset at 54GHz. The phased-array performance is measured using an internal test option and achieves 12dB peak-to-null ratio with two transmit and receive elements active.
\r\n\r\nWhile the 24GHz and 77GHz array are multiple-input single-output systems, higher-order phase-shifting and combining techniques can be used to achieve arrays with multiple outputs, with beams focused on different directions concurrently. Toward this end, a 60GHz bidirectional RF-combined phased array front-end is implemented in SiGe BiCMOS, using a hybrid parallel/series phase-shift approach that reduces the requirements of the on-chip phase shifters, enabling RF signal combining. The four-element array enables simultaneous illumination of two angles of incidence and includes amplitude control, as well as continuous phase adjustment. The front-end has a noise figure lower than 6.9dB at 60GHz and the array achieves full spatial coverage with peak-to-null ratio higher than 25dB. The four-element front-end consumes 265mW and occupies 4.6mm2 of die area.
", "doi": "10.7907/SGZC-FD54", "publication_date": "2007", "thesis_type": "phd", "thesis_year": "2007" }, { "id": "thesis:3062", "collection": "thesis", "collection_id": "3062", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08092005-100809", "primary_object_url": { "basename": "Final_Thesis.pdf", "content": "final", "filesize": 7751861, "license": "other", "mime_type": "application/pdf", "url": "/3062/1/Final_Thesis.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Signal Integrity Issues in High-Speed Wireline Links: Analysis and Integrated System Solutions", "author": [ { "family_name": "Analui", "given_name": "Behnam", "clpid": "Analui-Behnam" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Bruck", "given_name": "Jehoshua", "clpid": "Bruck-J" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Tai", "given_name": "Yu-Chong", "clpid": "Tai-Yu-Chong" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This work focuses on the basic signal integrity issues of high-speed wireline links. It bridges the gap between optimum system design and circuit design for such links by: (1) understanding the effects of the system parameters on the bit error rate (BER), (2) introducing circuit architectures for the realization of systems that minimize the BER, and (3) demonstrating integrated circuit prototypes that verify the solutions.
\r\n\r\nFirst, we develop a theory that analytically relates the data link BER to the system characteristics, e.g., the channel response, the pre-amplifier bandwidth, and the transmitter clock jitter. We generate the BER contours to find the optimum receiver bandwidth as well as the optimum sampling point and its associated timing margin. We also develop the theory of the data-dependent jitter (DDJ), which is a significant component of the timing jitter in high-speed links. We provide an analytical distribution function for the DDJ of an arbitrary linear time-invariant system and include the impact of the DDJ on the BER.
\r\n\r\nSecond, we propose a bandwidth enhancement method for wideband amplifiers. This is useful for the realization of high-speed links in technologies that suffer from large parasitic components. The method leverages two-port broadband matching to enable amplifier stages to achieve their maximum gain-bandwidth product. We demonstrate a 10Gb/s CMOS 0.18um amplifier with this technique that has 2.4 times the bandwidth improvement over a design that does not apply the technique.
\r\n\r\nThird, we develop an eye-opening monitor (EOM) that enables full integration of adaptive equalizers. The EOM evaluates the signal eye diagram quality and reports a quantitative measure, which is correlated to the signal integrity. We demonstrate a prototype in 0.13um standard CMOS that operates up to 12.5Gb/s and has 68dB error dynamic range.
\r\n\r\nFinally, we introduce an instantaneous clockless demultiplexer for burst-mode communication applications. We propose a clockless finite state machine that recovers and demultiplexes the received burst of data instantaneously. The architecture consists of a combinational logic structure and a bit-period-delayed feedback loop. We demonstrate a 1:2 clockless demultiplexer based on this concept in SiGe BiCMOS technology that operates at 7.5Gb/s.
", "doi": "10.7907/GGMB-0J23", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:1098", "collection": "thesis", "collection_id": "1098", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03242006-132815", "primary_object_url": { "basename": "Thesis(sanggeun)_final.pdf", "content": "final", "filesize": 3073399, "license": "other", "mime_type": "application/pdf", "url": "/1098/1/Thesis(sanggeun)_final.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Design and Stability Analysis Techniques for Switching-Mode Nonlinear Circuits: Power Amplifiers and Oscillators", "author": [ { "family_name": "Jeon", "given_name": "Sanggeun", "orcid": "0000-0001-7453-2331", "clpid": "Jeon-Sanggeun" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Stancil", "given_name": "Daniel D.", "clpid": "Stancil-D-D" }, { "family_name": "Doyle", "given_name": "John Comstock", "clpid": "Doyle-J-C" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "A design technique for kW level switching mode power amplifiers is presented. Several push pull pairs, independently tuned to Class E/Fodd, are combined by a distributed active transformer. The zero voltage switching (ZVS) condition is investigated and modified for the Class-E/Fodd amplifier with a non-ideal output transformer. All lumped elements including the DAT, the transistor package, and the input power distribution network are modeled and optimized to achieve the ZVS condition and the high drain efficiency. Two power amplifiers are implemented at 29 MHz, following the technique. The amplifier with two push pull pairs combined exhibits 1.5 kW output power with 85 % drain efficiency and 18 dB gain. When four push pull pairs are combined, an output power of 2.7 kW is achieved with 79 % drain efficiency and 18 dB gain.
\r\n\r\nNonlinear stability analysis techniques, based on an auxiliary generator and pole zero identification, are introduced to predict and eliminate the instabilities of power amplifiers. The techniques are applied to two switching mode power amplifiers that exhibited different instabilities during the measurements. Self-oscillation, chaos, and hysteresis of a Class E/Fodd amplifier with a distributed active transformer are investigated by the stability and bifurcation analysis tools. An in-depth analysis of the oscillation mechanism is also carried out, which enables an efficient determination of the topology and location of the required global stabilization network. As the other application, the anomalous behavior observed in a Class-E power amplifier is analyzed in detail. It involves hysteresis in the power-transfer curve, self oscillation, harmonic synchronization, and noisy precursors. To correct the amplifier performance, a new technique for elimination of the hysteresis is proposed, based on bifurcation detection through a single simulation on harmonic-balance software. Also, investigated are the circuit characteristics that make the noisy precursors observable in practical circuits and a technique is derived for their elimination from the amplifier output spectrum. All of the stabilization and correction of the amplifiers are experimentally validated.
\r\n\r\nA simple nonlinear technique for the design of high efficiency and high-power switching-mode oscillators is presented. It combines existing quasi-nonlinear methods and the use of an auxiliary generator in harmonic balance. The auxiliary generator enables the oscillator optimization to achieve high output power and dc to rf conversion efficiency without affecting the oscillation frequency. It also imposes a sufficient drive on the transistor to enable the switching mode operation with high efficiency. The oscillation start-up condition and the steady state stability are analyzed with the pole-zero identification technique. The influence of the gate bias on the output power, efficiency, and stability is also investigated. A Class E oscillator is demonstrated using the proposed technique. The oscillator exhibits 75 W with 67 % efficiency at 410 MHz.
", "doi": "10.7907/V4YT-YM88", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:673", "collection": "thesis", "collection_id": "673", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02182006-133932", "primary_object_url": { "basename": "dissertation_final.pdf", "content": "final", "filesize": 1514037, "license": "other", "mime_type": "application/pdf", "url": "/673/1/dissertation_final.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Design and Analysis of High-Efficiency L-Band Power Amplifiers", "author": [ { "family_name": "Wang", "given_name": "Feiyu", "clpid": "Wang-Feiyu" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Moussessian", "given_name": "Alina", "clpid": "Moussessian-A" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Discrete solid-state high-power amplifiers are among the important circuit components in today\u2019s wireless communications and remote-sensing applications. As the device technologies continue to improve, there are new opportunities and new challenges presented to power amplifier designers. This thesis presents novel techniques in the design and the analysis of L-band high-efficiency power amplifiers, which may be used in many communications and radar applications.
\r\n\r\nIn this work, high-efficiency power amplifier topologies are discussed and implemented. The goal is to push the boundary of output power, operating frequency, efficiency and bandwidth. Also, the design of a key passive component, a balanced-to-unbalanced transformer (balun) is discussed in detail. Some new designs of the baluns are shown, and the results show advantages of these baluns over some of the traditional work at L-band.
\r\n\r\nThe stability analysis of power amplifiers is one of the most critical and the most challenging aspects of power amplifier design. This work shows an analysis technique, which accurately predicts the oscillations in power amplifiers. Using the technique, different stabilization techniques and circuits are designed and implemented.
", "doi": "10.7907/CJGR-TF04", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:4457", "collection": "thesis", "collection_id": "4457", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-11082005-204747", "primary_object_url": { "basename": "Title.pdf", "content": "final", "filesize": 26939, "license": "other", "mime_type": "application/pdf", "url": "/4457/3/Title.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "High-Q Microcavities: Optomechanical Nonlinearities, Measurement Techniques and Applications", "author": [ { "family_name": "Rokhsari Azar", "given_name": "Hossein", "clpid": "Rokhsari-Azar-Hossein" } ], "thesis_advisor": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" } ], "thesis_committee": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Crosignani", "given_name": "Bruno", "clpid": "Crosignani-B" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Pickar", "given_name": "Kenneth A.", "clpid": "Pickar-K-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optical microresonators have historically been perceived as structures that could efficiently confine optical energies. This is due to their exceedingly low losses at optical frequencies. This thesis has, for the first time, explored these structures in a starkly different frequency range. Optical microcavities like any other structure have mechanical eigenmodes or resonant modes of vibration with quality-factors representing the efficiency of energy storage at mechanical frequencies. It is shown here that micron size of these structures results in vibrations at radio frequencies (~1-100 MH), about seven orders of magnitude apart from the optical frequencies (~100 THz). Mechanical quality factors in excess of 5,000 are measured for toroidal microcavities revealing a heretofore unknown potential of these structures in storing energy at frequencies remarkably distant from their optical resonant modes. \r\n\r\nThis thesis describes how radiation-pressure or the force due to impact of photons could result in exceptionally strong couplings between the mechanical and optical resonators collocated within the same device. The discovered optomechanical coupling present in toroid microcavities is shown to reach such a high level that regenerative mechanical oscillations of the cavity structure are initiated with only micro-Watts of optical power. This is the first demonstration of radiation-pressure-induced mechanical oscillations in any type of optomechanical system. Embodied within a microscale, chip-based device, this mechanism can benefit both research into macroscale quantum mechanical phenomena and improve the understanding of the mechanism within the context of Laser interferometer gravitational-wave observatory (LIGO). It also suggests that new technologies are possible that will leverage the phenomenon within photonics.\r\n\r\nDifferent physical functionalities are also realized in this thesis by a combination of ultra-high-Q microtoroids and extremely low-loss tapered optical fibers for efficient delivery of optical power to these structures. Using these tools an almost ideal optical band-pass filter is designed with efficiencies solely limited by intrinsic losses of the optical resonator. These intrinsic loss mechanisms are experimentally studied and differentiated by a powerful technique based on thermal nonlinearities of the microcavity material. By taking advantage of slow response times of thermal effects, an innovative pump and probe technique is also developed to unveil and measure the Kerr nonlinearity in microcavities, for the first time, at room temperature.", "doi": "10.7907/CVT6-8J70", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:3834", "collection": "thesis", "collection_id": "3834", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09302005-024349", "primary_object_url": { "basename": "thesis_xiang_final.pdf", "content": "final", "filesize": 3505176, "license": "other", "mime_type": "application/pdf", "url": "/3834/1/thesis_xiang_final.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Microwave Integrated Phased Array Receivers in Silicon", "author": [ { "family_name": "Guan", "given_name": "Xiang", "clpid": "Guan-Xiang" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "D'Addario", "given_name": "Larry R.", "clpid": "D'Addario-L-R" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Microwave integrated systems in silicon provide a low cost, low power and high yield solution for wideband data communication, radar, and many other applications. Phased-array systems are capable of steering the radiation beam by electronic means, emulating the behavior of a directional antenna. This dissertation is dedicated to presenting various techniques to implement microwave integrated phased-array receivers in silicon-based technologies in the context of three design examples.
\r\n\r\nA 24-GHz 0.18-\u00b5m complementary metal oxide semiconductor (CMOS) front-end was demonstrated. The front-end consists of a low noise amplifier (LNA) and a mixer. The LNA utilizes a novel topology common-gate with resistive feedthrough to obtain low-noise performance. The entire front-end achieves a 7.7dB noise figure and a 27.5dB power gain.
\r\n\r\nA fully integrated 8-element 24-GHz silicon germanium (SiGe) phased array receiver was implemented. The receiver uses two-step downconversion and local oscillator (LO) phase shifting with 4-bit resolution. The signal is combined at the 4.8-GHz intermediate frequency. The 16 phases of 19.2-GHz LO signal are generated with a voltage controlled oscillator (VCO) and symmetrically distributed to the phase selectors at all path. Appropriate phase sequence is applied to the phase distribution transmission lines to minimize mismatch. An integrated frequency synthesizer locks the 19.2-GHz VCO output to a 75-MHz external reference. Measured array patterns show a peak-to-null ratio of more than 20dB and a beam steering range covering all signal incident angles.
\r\n\r\nAn integrated 4-element 77-GHz SiGe wideband phased-array transceiver was implemented. Two-step conversion is used at both the receiver and the transmitter. A differential phase of 52 GHz is generated by the VCO and distributed to all RF paths at the transmitter and receiver. The phase shifting is performed at the LO ports of the RF mixers using continuous analog phase shifters. The quadrature signal of the second LO frequency is generated by dividing the VCO frequency by a factor of 2 using a cross-coupled injection-locked frequency divider. The signal combining is performed at IF with an active combining amplifier. The receiver achieves a 41dB gain at 80 GHz with 3 GHz of bandwidth. The 52-GHz-to-50MHz frequency divider chain obtains 7% locking range.
", "doi": "10.7907/E5GE-EP91", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:407", "collection": "thesis", "collection_id": "407", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01302006-154842", "primary_object_url": { "basename": "Buckwalter_Thesis01_06.pdf", "content": "final", "filesize": 8288834, "license": "other", "mime_type": "application/pdf", "url": "/407/1/Buckwalter_Thesis01_06.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Deterministic Jitter in Broadband Communication", "author": [ { "family_name": "Buckwalter", "given_name": "James Franklin", "orcid": "0000-0002-9390-0897", "clpid": "Buckwalter-James-Franklin" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Soyuer", "given_name": "Mehmet", "clpid": "Soyuer-M" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The past decade has witnessed a drastic change in the design of high-speed serial links. While Silicon fabrication technology has produced smaller, faster transistors, transmission line interconnects between chips and through backplanes have not substantially improved and have a practical bandwidth of around 3GHz. As serial link speeds increase, new techniques must be introduced to overcome the bandwidth limitation and maintain digital signal integrity. This thesis studies timing issues pertaining to bandwidth-limited interconnects. Jitter is defined as the timing uncertainty at a threshold used to detect the digital signal. Reliable digital communication requires minimizing jitter.
\r\n\r\nThe analysis and modeling presented here focuses on two types of deterministic jitter. First, dispersion of the digital signal in a bandwidth-limited channel creates data-dependent jitter. Our analysis links data sequences to unique timing deviations through the channel response and is shown for general linear time-invariant systems. A Markov model is constructed to study the impact of jitter on the operation of the serial link and provide insight in circuit performance. Second, an analysis of bounded-uncorrected jitter resulting from crosstalk induced in parallel serial links is presented.
\r\n\r\nTiming equalization is introduced to improve the signal integrity of high-speed links. The analysis of deterministic jitter leads to novel techniques for compensating the timing ambiguity in the received data. Data-dependent jitter equalization is discussed at both the receiver, where it complements the operation of clock and data recovery circuits, and as a phase pre-emphasis technique. Crosstalk-induced, bounded-uncorrected jitter can also be compensated. By detecting electromagnetic modes between neighboring serial links, a transmitter or receiver anticipates the timing deviation that has occurred along the transmission line.
\r\n\r\nFinally, we discuss a new circuit technique for submillimeter integrated circuits. Demands of wireless communication and the high speed of Silicon Germanium transistors provide opportunities for unique radio architectures for submillimeter integrated circuits. Scalable, fully-integrated phased arrays control a radiated beam pattern electronically through tiling multiple chips. Coupled-oscillator arrays are used for the first time to subharmonically injection-lock across a chip or between multiple chips to provide phase coherence across an array.
", "doi": "10.7907/EGRD-TZ84", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:2057", "collection": "thesis", "collection_id": "2057", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05252006-160420", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 8602082, "license": "other", "mime_type": "application/pdf", "url": "/2057/1/thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Integrated Ultrafast Nonlinear Optical Devices in Silicon", "author": [ { "family_name": "Hochberg", "given_name": "Michael", "clpid": "Hochberg-Michael" } ], "thesis_advisor": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "thesis_committee": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Doll", "given_name": "Theodore", "clpid": "Doll-T" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Silicon-on-insulator (SOI) provides an intriguing system for developing massively integrated optics. By leveraging the processes and systems developed for electronics fabrication, it is possible to make highly repeatable devices where complexity can be scaled up through the use of wafer-scale batch fabrication. Because the mode concentration in silicon waveguides is two orders of magnitude higher than in fibers, it is possible to construct very compact nonlinear optical devices within this system, enabling the miniaturization and integration of ultrafast nonlinear devices. We have developed a library of devices, including both dielectric and plasmonic waveguides, as well as resonators, splitters, and a variety of other basic optical components.
\r\n\r\nUsing these components to construct integrated devices of moderate complexity, we have demonstrated Pockels\u2019 Effect-based ring modulators, optical rectification-based detectors, four-wave mixing devices, and ultrafast intensity modulators, which operate at speeds in excess of 2 Terahertz. By integrating optical polymers through evanescent coupling to high-mode-confinement silicon waveguides, the effective nonlinearity of the waveguides can be greatly increased. The combination of high mode confinement, multiple integrated optical components, and high nonlinearity produces all-optical ultrafast devices operating at power levels compatible with modern continuous-wave telecommunication systems. Although far from commercial modulator standards in terms of extinction, these modulator devices are a first step toward large scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than existing free-carrier-based silicon devices.
\r\n", "doi": "10.7907/8124-DA56", "publication_date": "2006", "thesis_type": "phd", "thesis_year": "2006" }, { "id": "thesis:2332", "collection": "thesis", "collection_id": "2332", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05312005-225644", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 2726540, "license": "other", "mime_type": "application/pdf", "url": "/2332/1/thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Linearized and High Frequency Electrooptic Modulators", "author": [ { "family_name": "Cummings", "given_name": "Uri Vaughan", "clpid": "Cummings-Uri-Vaughan" } ], "thesis_advisor": [ { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "thesis_committee": [ { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Schaffner", "given_name": "James H.", "clpid": "Schaffner-J-H" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "An analysis is performed of many standard and linearized electrooptic modulators known in the industry. The transfer functions of these modulators are evaluated under a consistent set of performance figures of merit, which are gain and spur-free dynamic range, using a canonical set of optical link parameters. The tolerance of the needed precision of the parameters of the linearization mechanisms of all of these modulators is compared over the entire interesting range of noise bandwidth.
\r\n\r\nA computer program was written to analyze the frequency dependence of any modulator transfer function under any set of functional inputs. The program is used to illustrate and compare the frequency dependence of the figures of merit of all of the modulators for which a d-c analysis was performed. Further analysis looks at the effect of greater noise-bandwidth and recovering the frequency-dependent degradation of gain and dynamic range through re-phasing techniques. The gain of directional couplers is analyzed in-depth.
\r\n\r\nTwo novel modulator schemes are produced. The first uses reflective wave techniques to retime the electrical and optical waves half way through the modulator. The second uses fabrication geometry and properties of the linearization technique to make a more robust modulator (applicable to three of the modulators analyzed).
\r\n\r\nA 94 GHz antenna-coupled directional coupler modulator was initially demonstrated using an old modulator chip from Finbar Sheehy. A peculiar bug with the chip was uncovered. And a new modulator experiment was constructed and many aspects of the experimental apparatus were optimized. Though the revised experiment ultimately did not yield modulation side bands, it did couple a 94 GHz microwave signal into the optical waveguide, and many interesting challenges of high frequency electrooptic modulator fabrication were evaluated and improved upon.
", "doi": "10.7907/GTD7-V873", "publication_date": "2005", "thesis_type": "phd", "thesis_year": "2005" }, { "id": "thesis:5228", "collection": "thesis", "collection_id": "5228", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06092005-112430", "primary_object_url": { "basename": "JustinBoland.pdf", "content": "final", "filesize": 12677604, "license": "other", "mime_type": "application/pdf", "url": "/5228/1/JustinBoland.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Micro Electret Power Generators", "author": [ { "family_name": "Boland", "given_name": "Justin Scott", "clpid": "Boland-Justin-Scott" } ], "thesis_advisor": [ { "family_name": "Tai", "given_name": "Yu-Chong", "clpid": "Tai-Yu-Chong" } ], "thesis_committee": [ { "family_name": "Tai", "given_name": "Yu-Chong", "clpid": "Tai-Yu-Chong" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Pickar", "given_name": "Kenneth A.", "clpid": "Pickar-K-A" }, { "family_name": "Hunt", "given_name": "Melany L.", "clpid": "Hunt-M-L" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The taming of electricity and its widespread use allows people to see in the dark, to speak to one another instantaneously across the earth, and it allows retrieval of data from instruments sent out of the solar system. It is right to expect that the uses and demand for electricity will continue to grow, and to extend the ability to generate electricity; here two new micromachined devices for converting mechanical energy into electrical energy are presented. Aided by the wealth of micromachining process technology, generators that use an oscillatory motion to modify the physical structure of a capacitor with a built-in electric field provided by a permanent electret have been designed, built, and tested. The electret creates an electric field inside the capacitor structure, which induces mirror charge at some potential. The modification of the capacitor then generates an alternating displacement current through an external circuit, which provides useful electrical power. The electret microphone is a similar well known device for converting pressure waves into electrical signals by varying the distance between two charged capacitive plates. This work explores and proves feasible the ability to use mechanical forces to change the overlapping area of a charged capacitor structure and using mechanical forces to move a liquid into the gap of a charged capacitor structure, changing its permittivity to produce electricity. This work demonstrates 2.5mW of power from a 2cm diameter rotary generator at 12kRPM and 10[micro]w for a 0.1cm3 linear shaking generator at 60Hz.\r\n", "doi": "10.7907/B16C-NT21", "publication_date": "2005", "thesis_type": "phd", "thesis_year": "2005" }, { "id": "thesis:5197", "collection": "thesis", "collection_id": "5197", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05242005-172142", "primary_object_url": { "basename": "thesis_ch1.pdf", "content": "final", "filesize": 273247, "license": "other", "mime_type": "application/pdf", "url": "/5197/1/thesis_ch1.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "A Solid-state Atomic Frequency Standard", "author": [ { "family_name": "White", "given_name": "Christopher John", "clpid": "White-Christopher-John" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Weitekamp", "given_name": "Daniel P.", "clpid": "Weitekamp-D-P" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Roukes", "given_name": "Michael Lee", "clpid": "Roukes-M-L" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The thesis describes a new class of frequency reference. The frequency source uses the same operating principle as a passive atomic frequency standard; however, the device is entirely solid-state, removing many cost and reliability issues associated with gas-phase atomic clocks. More specifically, the \"atomic resonance\" is derived from zero-field magnetic resonance transitions of the vanadium ion in a cubic crystal lattice. The characteristics of these resonances will be described in detail. The apparatus for measuring the \"atomic\" resonances uses a radio-frequency resonant cavity and frequency discriminator circuit. Using integrated circuits, the radio-frequency signal processing functions can be implemented at very low cost in a reliable manufacturing process. We discuss the system design and the measurement sensitivity. Advantages of the new frequency reference may include immunity to vibration and reduced aging compared to crystal oscillators.", "doi": "10.7907/ATKE-YX40", "publication_date": "2005", "thesis_type": "phd", "thesis_year": "2005" }, { "id": "thesis:2423", "collection": "thesis", "collection_id": "2423", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06032005-115306", "primary_object_url": { "basename": "Yang_l_2005.pdf", "content": "final", "filesize": 10395220, "license": "other", "mime_type": "application/pdf", "url": "/2423/3/Yang_l_2005.pdf", "version": "v6.0.0" }, "type": "thesis", "title": "Fabrication and Characterization of Microlasers by the Sol-Gel Method", "author": [ { "family_name": "Yang", "given_name": "Lan", "orcid": "0000-0002-9052-0450", "clpid": "Yang-Lan" } ], "thesis_advisor": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" } ], "thesis_committee": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Yang", "given_name": "Changhuei", "clpid": "Yang-Changhuei" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The present study explores the application of new materials systems for low threshold microlasers, and characterization of the microcavities. The sol-gel method is used for gain functionalization of high-Q microcavities. A detailed procedure for preparation of the sol-gel films by the spin-on or dip-coating method is presented. The effect of different process conditions on the properties and microstructure of the thin films is investigated through Fourier Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), and etching rate test.
\r\n\r\nSurface gain functionalization of microsphere cavities is fabricated by coating the microsphere with a thin layer of Er\u00b3\u207a-doped sol-gel films. The optical gain is due to the population inversion of rare earth ions in the sol-gel films. A fiber taper is used to both couple the pump power into and extract the laser power out of the microsphere laser. The laser dynamics change between continuous-wave and pulsating operation by varying the doping concentration and the thickness of the sol-gel films outside the microsphere.
\r\n\r\nSurface functionalization is also achieved on the microtoroid on a single silicon chip, which can be fabricated in parallel using wafer-scale processing and has characteristics that are more easily controlled than microsphere. The microtoroid can be selectively coated only at the periphery by making use of the variation of etching rate (in buffered HF) of sol-gel films with different degrees of densification. The laser performance of the gain functionalized microtoroids is investigated. Highly confined whispering gallery modes make possible single-mode microlasers. This work also shows that the high Q microtoroid laser has a linewidth much lower than 300 kHz.
\r\n\r\nThe thesis explores fabrication of high Q microcavities directly from the sol-gel silica films deposited on a single silicon wafer. Quality factor as high as 2.5 x 10\u2077 at 1561 nm is obtained in toroidal microcavities formed of silica sol-gel, which allows Raman lasing at absorbed pump power below 1 mW. Additionally, Er\u00b3\u207a-doped microlasers are fabricated from Er\u00b3\u207a-doped sol-gel layers with control of the laser dynamics possible by varying the erbium concentration of the starting sol-gel material. Continuous lasing with a record threshold of 660 nW for erbium-doped microlaser on a silicon wafer is also obtained.
\r\n\r\nAnalytic formulas are derived to predict the laser performance, such as the laser output power, the threshold power, and the differential quantum efficiency, under different loading condition, i.e. the air gap between the fiber-taper coupler and the cavities. The effect of Er3+ concentration on the minimum threshold is also investigated. In addition, we present a theoretical model in which we include paired ions as the saturable absorber. It shows that self-pulsing operation can be expected with paired-ions-induced quenching in the system. The pulsation frequency increases linearly with the square root of the pumping level, which is consistent with the experimental observation.
", "doi": "10.7907/HHQ8-VC25", "publication_date": "2005", "thesis_type": "phd", "thesis_year": "2005" }, { "id": "thesis:2146", "collection": "thesis", "collection_id": "2146", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05272005-113247", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 8099301, "license": "other", "mime_type": "application/pdf", "url": "/2146/1/thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Ultra-High-Q Planar Microcavities and Applications", "author": [ { "family_name": "Armani", "given_name": "Deniz Karapetian", "clpid": "Armani-Deniz-Karapetian" } ], "thesis_advisor": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" } ], "thesis_committee": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Ultra-high-Q (UHQ) silica microspheres have found research applications in diverse fields ranging from telecommunications to nonlinear optics to biological and chemical sensing. However, despite having quality factors greater than 108, the silica microsphere has not moved to an industrial setting because of several major drawbacks. The most hindering is the manual fabrication technique used that makes tight process control difficult and integration with other optical or electrical components impossible. Despite the strong desire to fabricate an integrated UHQ microresonator on a planar substrate, the highest quality factor achieved for any micro-fabricated planar micro-cavity (at the time of my first publication) was over 4 orders of magnitude lower than for silica microspheres. In this thesis, a process for creating planar micro-cavities with Q factors in excess of 400 million on silicon wafers is demonstrated. The advantage of these planar ultra-high-Q (UHQ) microtoroid resonators is that they successfully overcome the previously mentioned drawbacks of silica microsphere resonators while maintaining nearly identical, if not better, performance characteristics. Additionally, due to the planar nature of these new devices, functionality has been integrated in-situ while maintaining UHQ for the first time, such as active resonant frequency tuning, coupling control, and low-threshold lasing.", "doi": "10.7907/EZHA-VY23", "publication_date": "2005", "thesis_type": "phd", "thesis_year": "2005" }, { "id": "thesis:1909", "collection": "thesis", "collection_id": "1909", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05212004-015508", "primary_object_url": { "basename": "Thesis_DaiLu.pdf", "content": "final", "filesize": 7365248, "license": "other", "mime_type": "application/pdf", "url": "/1909/1/Thesis_DaiLu.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Active Patch Array Design and Indoor Channel Modeling for Future Wireless Communications", "author": [ { "family_name": "Lu", "given_name": "Dai", "clpid": "Lu-Dai" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Effros", "given_name": "Michelle", "clpid": "Effros-M" }, { "family_name": "Pogorzelski", "given_name": "Ronald", "clpid": "Pogorzelski-R" }, { "family_name": "Bruck", "given_name": "Jehoshua", "clpid": "Bruck-J" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Indoor wireless LAN systems currently operate at ranges of up to 30 meters, with practical data rates of 10 Mbps. In order to achieve higher data rates, higher frequencies are under consideration. Smaller antennas are required at these frequencies, but path loss increases. To combat the large path loss and multipath, 24 GHz phased arrays are being considered. The advantage of a phased array is that it can form narrow beams to favored directions, and nulls to combat interference. A 24 GHz active antenna with a 5-element patch array is demonstrated that includes an integrated GaAs MMIC power amplifier and low noise amplifier chip. Bias switching is used for changing from transmit to receive. The measured active gain is 31 dB in receive and 35 dB in transmit. The measured noise figure in receive is 3.5 dB and the maximum output power in transmit is 22 dBm (158 mW). Indoor wireless channels are investigated at five different frequency bands. The understanding of the channel will help link budgeting and system planning for future wireless communication. An automatic testing system has been developed using remote control by LABVIEW. This increases testing efficiency and reduces near field interference from the operator. A combined E/H plane 2-D ray-tracing method is proposed to predict the channel performance. This approach accurately predicts path loss for both line-of-sight and non-line-of-sight paths. It predicts the delay spread in line-of-sight paths well but fails for non-line-of-sight paths. This could be due to the ignorance of some higher order paths with small amplitudes but near random phases. In addition, a 3-D simplified ray-tracing code is developed to for access point optimization and to predict human shadow effects.\r\n", "doi": "10.7907/PVB9-TH19", "publication_date": "2004", "thesis_type": "phd", "thesis_year": "2004" }, { "id": "thesis:2348", "collection": "thesis", "collection_id": "2348", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-06012004-104250", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 1718757, "license": "other", "mime_type": "application/pdf", "url": "/2348/1/thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Fiber-Coupled Ultra-High-Q Microresonators for Nonlinear and Quantum Optics", "author": [ { "family_name": "Spillane", "given_name": "Sean Michael", "clpid": "Spillane-Sean-Michael" } ], "thesis_advisor": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" } ], "thesis_committee": [ { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Kimble", "given_name": "H. Jeff", "clpid": "Kimble-H-J" }, { "family_name": "Bockrath", "given_name": "Marc William", "clpid": "Bockrath-M-W" }, { "family_name": "Painter", "given_name": "Oskar J.", "clpid": "Painter-O" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The ability to confine optical energy in small volumes for long periods of time is desirable for a number of applications, ranging from photonics and nonlinear optics, to fundamental studies in quantum electrodynamics. Whispering-gallery-mode microresonators are a promising cavity to study, due to the ability to obtain quality factors exceeding 100 million in micron-scale volumes. This thesis investigates the suitability of ultra-high-quality factor silica microresonators (both silica microspheres and silica toroidal microresonators) for nonlinear and quantum optics. Crucial to the actual use of these structures is the ability to efficiently excite and extract optical energy. The first part of this thesis investigates the ability to achieve near lossless coupling between a fiber-taper waveguide and a silica microresonator. It is shown that a coupling ideality (which is the fraction of energy coupled into the desired fiber mode) in excess of 99.97% is possible, meaning that optical energy can be coupled both to and from the optical resonator with near perfect efficiency.
\r\n\r\nUsing tapered fibers, low threshold stimulated Raman scattering is observed in both silica microspheres and silica microtoroids at record low incident pump powers below 100 microwatts, much lower than previous devices. High conversion efficiencies (>35%) are also realized. Furthermore, the conditions for optimized performance of both stimulated Raman scattering and parametric oscillation in a microcavity are described.
\r\n\r\nLastly, the suitability of toroidal microcavities for strong coupling cavity quantum electrodynamics is investigated. Numerical modeling of the optical modes demonstrates a significant reduction of modal volume with respect to spherical cavities, while retaining high quality factors. The extra degree of freedom of toroid microcavities can be used to achieve improved strong-coupling characteristics, and numerical results for atom-cavity coupling strength, critical atom number and critical photon numbers for cesium are calculated and shown to exceed values currently possible using Fabry-Perot cavities. Modeling predicts atom-cavity coupling rates exceeding 700 MHz and critical atom numbers approaching 10\u207b\u2077.
", "doi": "10.7907/MKYH-WV47", "publication_date": "2004", "thesis_type": "phd", "thesis_year": "2004" }, { "id": "thesis:1303", "collection": "thesis", "collection_id": "1303", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-04082003-150009", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 4740680, "license": "other", "mime_type": "application/pdf", "url": "/1303/2/thesis.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Millimeter-Wave MMICs and Applications", "author": [ { "family_name": "Morgan", "given_name": "Matthew Alexander", "clpid": "Morgan-Matthew-Alexander" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Pogorzelski", "given_name": "Ronald", "clpid": "Pogorzelski-R" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "As device technology improves, interest in the millimeter-wave band grows. Wireless communication systems migrate to higher frequencies, millimeter-wave radars and passive sensors find new solid-state implementations that promise improved performance, and entirely new applications in the millimeter-wave band become feasible. The circuit or system designer is faced with a new and unique set of challenges and constraints to deal with in order to use this portion of the spectrum successfully. In particular, the advantages of monolithic integration become increasingly important.
\r\n\r\nThis thesis presents many new developments in Monolithic Millimeter-Wave Integrated Circuits (MMICs), both the chips themselves and systems that use them. It begins with an overview of the various applications of millimeter waves, including a discussion of specific projects that the author is involved in and why many of them demand a MMIC implementation. In the subsequent chapters, new MMIC chips are described in detail, as is the role they play in real-world projects. Multi-chip modules are also presented with specific attention given to the practical details of MMIC packaging and multi-chip integration. The thesis concludes with a summary of the works presented thus far and their overall impact on the field of millimeter-wave engineering.
", "doi": "10.7907/MW4Z-2Q79", "publication_date": "2003", "thesis_type": "phd", "thesis_year": "2003" }, { "id": "thesis:1693", "collection": "thesis", "collection_id": "1693", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05092003-135830", "primary_object_url": { "basename": "title_TOC.pdf", "content": "final", "filesize": 85190, "license": "other", "mime_type": "application/pdf", "url": "/1693/6/title_TOC.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Detection of DNA by Sequence Specific Fluorescent Polyamides", "author": [ { "family_name": "Rucker", "given_name": "Victor Clay", "clpid": "Rucker-Victor-Clay" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Grubbs", "given_name": "Robert H.", "clpid": "Grubbs-R-H" }, { "family_name": "Gray", "given_name": "Harry B.", "clpid": "Gray-H-B" }, { "family_name": "Hsieh-Wilson", "given_name": "Linda C.", "clpid": "Hsieh-Wilson-L-C" }, { "family_name": "Dervan", "given_name": "Peter B.", "clpid": "Dervan-P-B" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "local_group": [ { "literal": "div_chem" } ], "abstract": "This thesis covers the use of hairpin polyamides to achieve, most notably, HIV-1 LTR gene regulation and fluorescent detection of double stranded DNA. In Chapter 2 we discuss our collaboration with Professor David Margolis to study integrated HIV-1 latency in quiescent T-lymphocytes. Understanding latency in HIV-1 infection is of paramount importance for developing anti-HIV-1 therapeutics. Chapter 3 deals with the characterization of a special case of 2-beta-2 polyamide binding in the minor groove, and we discuss the use of (S)-2,4-diaminobutyric acid to influence polyamide specificity and orientation. In Chapter 4 we present data concerning the use of hairpin polyamides that, when unbound to DNA, quench the fluorescence of the xanthene fluorphore to which they are covalently attached. We cover experiments aimed at exploring the uses of this fluorescence phenomenon to optically detect double stranded DNA in a sequence specific manner, an issue of great importance as shown in the literature by the numerous denaturing assays for oligo detection by hybridization. In Chapter 5, the fruits of a collaboration with Alexander Dunn of Professor Gray's group, we attempt to define the mechanism whereby polyamides quench tetramethyl rhodamine fluorescence.", "doi": "10.7907/93KR-9543", "publication_date": "2003", "thesis_type": "phd", "thesis_year": "2003" }, { "id": "thesis:1813", "collection": "thesis", "collection_id": "1813", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05152003-144457", "primary_object_url": { "basename": "thesis_mookherjea.pdf", "content": "final", "filesize": 4999524, "license": "other", "mime_type": "application/pdf", "url": "/1813/1/thesis_mookherjea.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Coupled-Resonator Optical Waveguides and Multiplexed Solitons", "author": [ { "family_name": "Mookherjea", "given_name": "Shayan", "orcid": "0000-0001-9864-2367", "clpid": "Mookherjea-Shayan" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "thesis_committee": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Cohen", "given_name": "Donald S.", "clpid": "Cohen-D-S" }, { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Whether over micron-long or kilometer-long distances, periodic phenomena can strongly affect both the propagation and the confinement of optical pulses. Periodicities can be engineered through the structural design of optical waveguides, or they may manifest self-consistently from induced nonlinear polarizations. In light of recent developments in fabrication technologies for semiconductor waveguides, polymeric materials, and optical fiber, we show that both strongly- and weakly-nonlinear channels are promising for new devices and systems in optical communications. This thesis proposes and discusses applications of guided wave periodicities in the framework of photonic crystals (coupled-resonator optical waveguides as well as transverse Bragg resonance waveguides and amplifiers), nonlinear phenomena in photorefractive semiconductors, and the nonlinear evolution of temporal solitons in dispersion-managed fibers.
\r\n\r\nCoupled-resonator optical waveguides (CROWs) are composed of a periodic array of electromagnetic resonators, typically on the micron or sub-micron length scales. A photon in such a waveguide sees a periodic potential, and according to the Floquet-Bloch theorems, has a wavefunction that reflects this periodicity. CROWs have a unique dispersion relationship compared to other semiconductor waveguides, and can be used to slow down the speed of propagation, enhance nonlinear interactions such as second-harmonic generation and four-wave mixing, and form frozen soliton-type field distributions that use the optical Kerr nonlinearity to stabilize themselves against decay via adjacent-resonator or waveguide-resonator coupling.
\r\n\r\nIn optical fibers that possess the optical Kerr nonlinearity in addition to group-velocity dispersion, it is possible to propagate pulses with envelopes that \"breathe\" with distance, typically at kilometer or longer length scales. Such waveforms are characterized by a set of parameters, e.g., amplitude, chirp, etc., that vary in a periodic manner as the pulse propagates. Borrowing an idea from field theory, e.g., of classical pendulums, or quantum-mechanical elementary particles, the pulse envelope may be viewed as a particle traversing a trajectory in a phase space defined by its characteristic parameters. Distinct, non-overlapping trajectories are assigned as symbols of a multilevel communication code. Since it is the periodicity, arising from the Kerr nonlinearity, that generates this diversity in phase-space, there is no analog of this multiplexed system in linear optical transmission links. The overall bit-rate can be improved several fold above the current limits.
", "doi": "10.7907/9BYR-7J64", "publication_date": "2003", "thesis_type": "phd", "thesis_year": "2003" }, { "id": "thesis:1867", "collection": "thesis", "collection_id": "1867", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05192003-161134", "primary_object_url": { "basename": "final_master.pdf", "content": "final", "filesize": 5040312, "license": "other", "mime_type": "application/pdf", "url": "/1867/1/final_master.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Waveguide Packaging of Quasi-Optical Grid Amplifiers", "author": [ { "family_name": "Cheung", "given_name": "Chun Tung", "clpid": "Cheung-Chun-Tung" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Rosenberg", "given_name": "Jim", "clpid": "Rosenberg-J" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Quasi-optical amplifiers combining the output powers of hundreds of transistors have demonstrated the capability to deliver more than 10 Watts of power at millimeter wave frequencies. However, these amplifiers are large and expensive to manufacture. In this work, we attempt to find a compact, low-cost approach using metallic waveguide to package a grid amplifier. This thesis details the design and implementation of a grid amplifier packaged in waveguide. Frequency and time-domain simulation methods are used to calculate the field flatness and the small signal gain of the amplifier. Four different active grids packaged in waveguide will be reported. The first grid, operating at Ka-band, is fed with a waveguide and radiates its output into free space. The amplifier chip design was previously measured in free-space. This work demonstrates a small signal gain of 7 dB with output power of 5.5 W at 3-dB compression. The performance is similar to the same grid design measured in free-space. A second Ka-band grid amplifier packaged in waveguide for both input and output gives a small signal gain of 6 dB. The 3-dB compressed output power is 670 mW while the same amplifier measured in free-space gave 1.2 W output power. In order to further verify our active grid and packaging design methods, a V-band single-stage monolithic grid amplifier was designed and fabricated. A transmission grid amplifier and a reflection grid amplifier using this chip were fabricated. Both amplifiers have 2 dB small-signal gain at 58 GHz. In order to increase small-signal gain, a two-stage monolithic grid amplifier was designed and fabricated. A reflection approach was used to package this chip. Measured small-signal gain was 2.7 dB at 82 GHz.", "doi": "10.7907/KSGC-3G92", "publication_date": "2003", "thesis_type": "phd", "thesis_year": "2003" }, { "id": "thesis:2296", "collection": "thesis", "collection_id": "2296", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05302003-160130", "primary_object_url": { "basename": "Dissertation_HuiWu.pdf", "content": "final", "filesize": 2612049, "license": "other", "mime_type": "application/pdf", "url": "/2296/1/Dissertation_HuiWu.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Signal Generation and Processing in High-Frequency / High-Speed Silicon-Based Integrated Circuits", "author": [ { "family_name": "Wu", "given_name": "Hui", "clpid": "Wu-Hui" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Tai", "given_name": "Yu-Chong", "orcid": "0000-0001-8529-106X", "clpid": "Tai-Yu-Chong" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "High-frequency/high-speed integrated circuits become increasingly important because of the strong demand for higher data rate and lower power consumption, and they rely more on silicon-based technologies, which has the advantages of low cost, fast technological development and system-on-a-chip (SoC) capabilities. However, silicon technologies also present great challenges in high-frequency/high-speed integrated circuits. This work demonstrated that distributed circuit and injection locking are two enabling circuit techniques that can help overcome silicon limitations.
\r\n\r\nDistributed voltage-controlled oscillators (DVCO's) demonstrated the high-frequency capabilities of distributed circuits. The operation of distributed oscillators is analyzed and the general oscillation condition is derived, resulting in analytical expressions for the oscillation frequency and amplitude. Two tuning techniques are developed, namely, the inherent-varactor tuning and delay-balanced current-steering tuning. A complete analysis of the tuning techniques is also presented. CMOS and bipolar DVCO prototypes have been designed and fabricated in a commercial 0.35\u00b5m BiCMOS process. A 10-GHz CMOS DVCO achieves a tuning range of 12\\% and a phase noise of -103 dBc/Hz at 600 kHz frequency offset. A 12-GHz bipolar DVCO achieves a tuning range of 26% and a phase noise of -99 dBc/Hz at 600 kHz frequency offset. New DVCO architectures are also proposed to improve the performance.
\r\n\r\nThe distributed circuit technique is also used for equalization in high-speed fiber-optic systems, in which inter-symbol interference (ISI) caused by fibre dispersion imposes a major limitation. Compared to optical-domain methods and other electrical-domain methods, equalization with distributed transversal filters (DTF's) presents the most cost-effective and SoC-compatible solution. Prototype DTF's have been implemented in a commercial 0.18\u00b5m SiGe BiCMOS process for 10 Gpbs fiber-optic systems. A 7-tap DTF reduces the ISI of a 10 Gbps signal after 800m 50\u00b5m multi-mode fiber from 5 dB to 1.38 dB, and improves the BER from 10\u207b\u2075 to 10\u207b\u00b9\u00b2.
\r\n\r\nThe injection locking technique is applied in high-speed, low-power frequency dividers, namely, injection-locked frequency dividers (ILFD's). Based on the detailed analysis, shunt-peaking and oscillation-suppression techniques are developed to enhance the locking range. Prototypes are implemented in a commercial 0.35\u00b5m BiCMOS process using only CMOS transistors. A 19 GHz ILFD achieves a locking range of 1350 MHz with the power consumption of 1 mW. A 9 GHz ILFD achieves a locking range of 1490 MHz with the power consumption of 1.3 mW. Self-dividing oscillators are proposed to generate accurate low-phase-noise quadrature signals.
", "doi": "10.7907/51YY-3Y81", "publication_date": "2003", "thesis_type": "phd", "thesis_year": "2003" }, { "id": "thesis:2129", "collection": "thesis", "collection_id": "2129", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05272004-094928", "primary_object_url": { "basename": "Aoki_i_2002.pdf", "content": "final", "filesize": 26641555, "license": "other", "mime_type": "application/pdf", "url": "/2129/1/Aoki_i_2002.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Distributed Active Transformer for Integrated Power Amplification", "author": [ { "family_name": "Aoki", "given_name": "Ichiro", "clpid": "Aoki-Ichiro" } ], "thesis_advisor": [ { "family_name": "Janda", "given_name": "Kenneth C.", "clpid": "Janda-K-C" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Bruck", "given_name": "Jehoshua", "orcid": "0000-0001-8474-0812", "clpid": "Bruck-J" }, { "family_name": "Weinreb", "given_name": "Sander", "orcid": "0000-0002-9353-6204", "clpid": "Weinreb-S" }, { "family_name": "Tai", "given_name": "Yu-Chong", "orcid": "0000-0001-8529-106X", "clpid": "Tai-Yu-Chong" }, { "family_name": "Janda", "given_name": "Kenneth C.", "clpid": "Janda-K-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "A novel on-chip impedance transformation and power-combining technique, the distributed active transformer (DAT) is introduced. It overcomes the fundamental difficulties presented by silicon technology in the design of integrated rf power amplifiers. This technique efficiently combines several low-voltage push-pull amplifiers and simultaneously performs an impedance transformation to produce a larger output power while maintaining a 50\u03a9 match. It also uses virtual ac grounds and magnetic couplings extensively to eliminate the need for any off-chip component, such as tuned bonding wires or external inductors. Furthermore, it desensitizes the operation of the amplifier to the inductance of bonding wires making the design more repeatable.
\r\n\r\nIn this work, the performance of the introduced DAT structure is compared to that of conventional on-chip impedance transformation methods. Their fundamental power-efficiency limitations in the design of high-power fully-integrated amplifiers in standard silicon process technologies are analyzed and the DAT is demonstrated to be more efficient. Furthermore, different classes of power amplification operations and their use in DAT power amplifiers are studied.
\r\n\r\nTo demonstrate the feasibility of this concept several silicon integrated power amplifiers have been fabricated and measured including a 2.4-GHz, 2-W, 2-V truly fully-integrated power amplifier with 50\u03a9 on-chip input and output matching using 0.35\u00b5m CMOS transistors. It achieves a power added efficiency (PAE) of 41 % at this power level, demonstrating for the first time a truly fully-integrated watt-level GHz range CMOS power amplifier. It can also produce 450mW using a 1 V supply. A two stage DAT prototype, also at 2.4GHz using the same technology, operates with higher gain and lower supply voltage achieving 1-W output power, 30% PAE, and 14-dB gain with 1.15-V supply.
", "doi": "10.7907/6XMD-MR86", "publication_date": "2002", "thesis_type": "phd", "thesis_year": "2002" }, { "id": "thesis:967", "collection": "thesis", "collection_id": "967", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03162005-141416", "primary_object_url": { "basename": "Ham_d_2002.pdf", "content": "final", "filesize": 8325658, "license": "other", "mime_type": "application/pdf", "url": "/967/1/Ham_d_2002.pdf", "version": "v6.0.0" }, "type": "thesis", "title": "Statistical Electronics: Noise Processes in Integrated Communication Systems", "author": [ { "family_name": "Ham", "given_name": "Donhee", "clpid": "Ham-Donhee" } ], "thesis_advisor": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" } ], "thesis_committee": [ { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "Bruck", "given_name": "Jehoshua", "orcid": "0000-0001-8474-0812", "clpid": "Bruck-J" }, { "family_name": "Cross", "given_name": "Michael Clifford", "clpid": "Cross-M-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Tai", "given_name": "Yu-Chong", "orcid": "0000-0001-8529-106X", "clpid": "Tai-Yu-Chong" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents a comprehensive investigation of noise and thermodynamics in electronic circuits and systems. This study of \"statistical electronics\" spans two disciplines, statistical thermodynamics and electronic circuit engineering, and leads to a general picture that bridges electronics and statistical thermodynamics.
\r\n\r\nOur work on statistical electronics has both scientific and engineering implications. Scientifically, this work is an extensive study of statistical thermodynamics in the context of electrical circuits, which has made several significant contributions to the understanding of noise processes in electrical circuits. The technological importance is a demonstration of how the fundamental physical considerations evolve to practical high-performance novel circuit design. The power of our fundamental approach is demonstrated through several practical circuit examples.
\r\n\r\nFirst, our investigation of fluctuations in nonlinear electrical circuits provides deep insight into the nonlinear fluctuation phenomena. Especially, the study of fluctuations in nonlinear active devices constitutes an important sector in this investigation; verifying the physical soundness of the contemporary active device noise modeling and leading to clear understanding of fluctuation-dissipation relations in nonlinear devices.
\r\n\r\nSecond, we apply statistical electronics to noise problems involved in frequency conversion, an essential function in modern RF and microwave receivers. This study leads to two novel observations of noise figure degradation due to cyclostationary noise and conversion gain enhancement, both dependent on the size of energy storing elements. This novel behavior is experimentally verified with a direct measurement of integrated switching mixers. The results provide new insight into cyclostationary noise processes in frequency conversion and optimum deisgn for switching mixers.
\r\n\r\nThird, application of statistical electronics to noise in frequency generation by self-sustained oscillators leads to a new theory of oscillator noise. This study demonstrates the direct correspondence between the phase noise and the Einstein relation; revealing the underlying physics of oscillator noise. Our approach clarifies the fluctuation-dissipation relation in oscillator noise generation, establishing a link between currently available fluctuation-based and dissipation-based phase noise. models and leading to a clear definition of loaded quality factor of ail oscillator. The novel concepts of virtual damping and linewidth compression put resonators and oscillators in a unified framework, providing immediate design optimization insight. The power of this theoretical development is demonstrated through experimental measurements of various integrated oscillators.
\r\n\r\nOur work on statistical electronics combining circuit engineering and physical science has also resulted in other useful engineering methods, such as graphical optimization, noise simulations for computer-aided design (CAD), and time-varying filter theory.
", "doi": "10.7907/tgja-7y11", "publication_date": "2002", "thesis_type": "phd", "thesis_year": "2002" }, { "id": "thesis:1512", "collection": "thesis", "collection_id": "1512", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-04262005-152703", "primary_object_url": { "basename": "Kee_s_2002.pdf", "content": "final", "filesize": 36463553, "license": "other", "mime_type": "application/pdf", "url": "/1512/1/Kee_s_2002.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "The Class E/F Family of Harmonic-Tuned Switching Power Amplifiers", "author": [ { "family_name": "Kee", "given_name": "Scott David", "clpid": "Kee-Scott-David" } ], "thesis_advisor": [ { "family_name": "Readhead", "given_name": "Anthony C. S.", "clpid": "Readhead-A-C-S" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Hajimiri", "given_name": "Ali", "orcid": "0000-0001-6736-8019", "clpid": "Hajimiri-A" }, { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Weinreb", "given_name": "Sander", "orcid": "0000-0002-9353-6204", "clpid": "Weinreb-S" }, { "family_name": "Readhead", "given_name": "Anthony C. S.", "orcid": "0000-0001-9152-961X", "clpid": "Readhead-A-C-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\r\n\r\nA new family of harmonic-tuned switching amplifiers is introduced having the beneficial features of the class-E tuning while allowing improved performance to be achieved through additional harmonic tuning. This E/F family may be tuned to achieve the ZVS/ZdVS switching features characteristic of the class-E amplifier and, like the class-E tuning, accounts and compensates for the effect of the switch parallel capacitance. By tuning one or more overtones to the [...] tuning, however, the switching waveforms may be improved, lowering the peak voltage and reducing the RMS current. Additionally, the tolerance to large switch parallel capacitance is generally improved so that a larger switching device may be used, allowing reduction of the on-resistance. Due to these factors, the efficiency of E/F amplifiers is expected to exceed that of class E.\r\n\r\nTo demonstrate these advantages, methods of estimating the optimal efficiency of switching amplifiers using waveform properties are given. A general solution technique is then presented which allows the calculation of the ZVS tuning requirements and the resulting switching waveforms for an arbitrary harmonic tuning. Using these two tools, switching waveforms and resulting efficiency estimates are calculated for E/F amplifier tunings, which are then compared to class E.\r\n\r\nFinally, potential application areas of the E/F technique are explored, and measured results of several first-generation E/F amplifiers are presented. Aside from efficiency benefits, E/F amplifiers also may achieve load-invariance, dual- and multi-band operation, high volumetric power densities, and efficient integrated circuit implementation using the Aoki distributed active transformer power combining structure.\r\n", "doi": "10.7907/MD86-FX51", "publication_date": "2002", "thesis_type": "phd", "thesis_year": "2002" }, { "id": "thesis:5315", "collection": "thesis", "collection_id": "5315", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10212009-105023039", "primary_object_url": { "basename": "Sverdrup_l_2002.pdf", "content": "final", "filesize": 24649113, "license": "other", "mime_type": "application/pdf", "url": "/5315/1/Sverdrup_l_2002.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Lower Hybrid Current Drive Experiments on the Encore Tokamak", "author": [ { "family_name": "Sverdrup", "given_name": "Lawrence Henry", "clpid": "Sverdrup-Lawrence-Henry" } ], "thesis_advisor": [ { "family_name": "Vreeland", "given_name": "Thad", "clpid": "Vreeland-T" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" } ], "thesis_committee": [ { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Corngold", "given_name": "Noel Robert", "clpid": "Corngold-N-R" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Vreeland", "given_name": "Thad", "clpid": "Vreeland-T" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The work of this thesis concerns a technological aspect of a tokamak fusion power reactor. A toroidal current in tokamaks is necessary for plasma equilibrium. Ohmic heated tokamaks are inherently pulsed devices since the toroidal plasma current is essentially a single turn secondary of a transformer. A pulsed power reactor is undesirable for a number of reasons including thermal fatigue to material structures and other mechanical cycling effects. Various means to drive a continuous current have been studied. One of the more successful schemes has been to inject unidirectional lower hybrid plasma waves into a tokamak. The plasma waves Landau damp on the high velocity tail of the electron distribution, delivering wave momentum to electrons and generating plasma current.
\r\n\r\nThe results of early experiments produced two plasma physics problems. First, the current drive effect disappeared above a certain plasma density that depended in some way on the particulars of the experiment. This effect became known as the 'density limit' problem. Secondly, the phase velocities of the launched lower hybrid plasma waves in most experiments turned out to be so high that essentially no electrons in the high velocity tail of the electron distribution were available to interact with the plasma waves. Despite this, large currents were indeed driven in most of the experiments. Somehow the 'spectral gap' between the launch phase velocity of the wave and the Landau damping phase velocity was being bridged.
\r\n\r\nExperiments at Caltech on the Encore tokamak failed to produce the large driven currents seen in other experiments. The reason for this and simultaneously the cause of the density limit seen in the other experiments was explained by a relatively simple and appealing theory.
\r\n\r\nSmall driven currents were observed. Initially puzzling was the result that currents could be driven in the same toroidal direction regardless of the directionality of the launched lower hybrid waves. The Encore tokamak had a handedness. The cause of this handedness turned out to be a radial, horizontal, magnetic error field associated with the toroidal magnetic field which led to a horizontal spiraling of the toroidal field lines.
", "doi": "10.7907/27RZ-SM06", "publication_date": "2002", "thesis_type": "phd", "thesis_year": "2002" }, { "id": "thesis:2866", "collection": "thesis", "collection_id": "2866", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-07132001-112041", "primary_object_url": { "basename": "ashish_thesis.pdf", "content": "final", "filesize": 1170468, "license": "other", "mime_type": "application/pdf", "url": "/2866/1/ashish_thesis.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "All-Optical Logic Circuits Based on the Polarization Properties of Non-Degenerate Four-Wave Mixing", "author": [ { "family_name": "Bhardwaj", "given_name": "Ashish Ishwar Singh", "clpid": "Bhardwaj-Ashish-Ishwar-Singh" } ], "thesis_advisor": [ { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" } ], "thesis_committee": [ { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" }, { "family_name": "Fultz", "given_name": "Brent T.", "orcid": "0000-0002-6364-8782", "clpid": "Fultz-B-T" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Atwater", "given_name": "Harry Albert", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis investigates a new class of all-optical logic circuits that are based on the polarization properties of non-degenerate Four-Wave Mixing. Such circuits would be used in conjunction with a data modulation format where the information is coded on the states of polarization of the electric field. Schemes to perform multiple triple-product logic functions are discussed and it is shown that higher-level Boolean operations involving several bits can be implemented without resorting to the standard 2-input gates that are based on some form of switching. Instead, an entire hierarchy of more complex Boolean functions can be derived based on the selection rules of multi-photon scattering processes that can form a new class of primitive building blocks for digital circuits.
\r\n \r\nPossible applications of these circuits could involve some front-end signal processing to be performed all-optically in shared computer back-planes. As a simple illustration of this idea, a circuit performing error correction on a (3,1) Hamming Code is demonstrated. Error-free performance (Bit Error Rate of < 10\u207b\u2079) at 2.5 Gbit/s is achieved after single-error correction on the Hamming word with 50 percent errors. The bit-rate is only limited by the bandwidth of available resources. Since Four-Wave Mixing is an ultrafast nonlinearity, these circuits offer the potential of computing at several terabits per second. Furthermore, it is shown that several Boolean functions can be performed in parallel in the same set of devices using different multi-photon scattering processes. The main objective of this thesis is to motivate a new paradigm of thought in digital circuit design. Challenges pertaining to the feasibility of these ideas are discussed.
", "doi": "10.7907/CMAB-WF06", "publication_date": "2001", "thesis_type": "phd", "thesis_year": "2001" }, { "id": "thesis:6152", "collection": "thesis", "collection_id": "6152", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10212010-100027618", "primary_object_url": { "basename": "Cai_m_2001.pdf", "content": "final", "filesize": 9944794, "license": "other", "mime_type": "application/pdf", "url": "/6152/1/Cai_m_2001.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Optical Fiber Taper Coupled Glass Microsphere Resonators", "author": [ { "family_name": "Cai", "given_name": "Ming", "clpid": "Cai-Ming" } ], "thesis_advisor": [ { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" } ], "thesis_committee": [ { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" }, { "family_name": "Atwater", "given_name": "Harry Albert", "orcid": "0000-0001-9435-0201", "clpid": "Atwater-H-A" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis studies optical fiber taper coupled dielectric microsphere resonators and their applications. Fundamental properties including ideal coupling and critical coupling in an optical fiber taper to fused silica glass microsphere coupling system is investigated both theoretically and experimentally. A symmetrical dual-taper coupling configuration is proposed to obtain highly efficient power transfer from the taper coupler to the microsphere resonator. Applications as channel add/drop filters and microsphere lasers are also demonstrated.
\r\n\r\nThe physical essence of the fiber taper to silica microsphere is analyzed using a two-dimensional model. The relationship between the coupling strength and the cavity loss is unveiled. Adiabatic tapers and high-quality microspheres are fabricated and used to demonstrate actual coupling systems. Perfect agreement between the experimental results and the theoretical prediction is presented.
\r\n\r\nPower transfer from the taper to a microsphere resonator has been significantly improved by employing a dual-taper symmetrically coupling configuration. Up to -28 dB extinction at the central resonant wavelength has been measured.
\r\n\r\nWe then propose a device application of the taper-sphere-taper structure as a channel add/drop filter in the wavelength division multiplexing systems. For a filter with a bandwidth of 3.8 GHz and a dropping channel isolation of 26 dB, the bit-error-rate measurement shows no power penalty at 2.5 Gbit/s.
\r\n\r\nA 1.5 \u00b5m wavelength single-frequency fiber laser is also demonstrated using a single tapered fiber coupling to a highly doped erbium:ytterbium phosphate glass microsphere. The fiber taper serves the dual purpose of transporting optical pump power into the sphere and extracting the resulting laser emission. As low as 60 \u00b5W pump threshold and fiber-coupled output power as high as 3 \u00b5W with single mode operation are obtained. Imaging of photoluminescence from the sphere at visible wavelengths reveals the pump power is resonantly coupled into semiclassical orbits due to the strong absorption damping in the phosphate glass. A bi-sphere laser system consisting of two microspheres attached to a single fiber taper is also demonstrated.
\r\n\r\nFinally, a novel hybrid fiber taper, made from a combination of a 980 nm single mode fiber and a 1550 nm single mode fiber, is proposed and demonstrated as the microsphere laser coupler. Both the pump wave and laser emission are found to be more efficiently coupled to and from, respectively, the sphere modes. As high as 112 \u00b5W single-frequency laser output power is measured with a differential quantum efficiency of 12%.
", "doi": "10.7907/JB4C-VR78", "publication_date": "2001", "thesis_type": "phd", "thesis_year": "2001" }, { "id": "thesis:480", "collection": "thesis", "collection_id": "480", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02032004-163517", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 2085207, "license": "other", "mime_type": "application/pdf", "url": "/480/1/thesis.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Dual polarized and balanced receivers at millimeter and submillimeter wavelengths", "author": [ { "family_name": "Chattopadhyay", "given_name": "Goutam", "orcid": "0000-0001-7942-5025", "clpid": "Chattopadhyay-Goutam" } ], "thesis_advisor": [ { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "Hajimiri", "given_name": "Ali", "clpid": "Hajimiri-A" }, { "family_name": "Carlstrom", "given_name": "John E.", "clpid": "Carlstrom-J-E" }, { "family_name": "Weinreb", "given_name": "Sander", "clpid": "Weinreb-S" } ], "local_group": [ { "literal": "Caltech Submillimeter Observatory" }, { "literal": "Astronomy Department" }, { "literal": "div_eng" } ], "abstract": "Dramatic advances in millimeter and submillimeter wave receivers in recent years have resulted from the development of superconductor insulator superconductor (SIS) mixers, which now offer unsurpassed performance from 70 GHz to 1 THz. To increase the sensitivity of the receivers further at these frequencies, one needs to use dual-polarized and balanced receivers. When both the polarizations are received simultaneously, there is a square root of two improvement in the signal to noise ratio (SNR). Balanced mixers improve the sensitivity of receivers by suppressing local oscillator (LO) amplitude modulation (AM) noise and rejecting LO thermal noise. This thesis describes the design, fabrication and performance of mixers and components for low noise dual-polarized and balanced receivers at millimeter and submillimeter wavelengths both in quasi-optical and waveguide configurations. The quasi-optical receiver utilizes a novel cross-slot antenna on a silicon hyperhemispherical lens, two junction tuning circuits, niobium trilayer junctions, and an IF circuit containing a lumped element 180 degree hybrid. The antenna has four feed points, two for each polarization; and each feed point is coupled to a two-junction SIS mixer. For dual polarization operation, the mixer is mounted in such a way that a single LO can pump the junctions for both the polarizations. For the balanced receiver, the LO and the RF signals are coupled to the mixer in orthogonal polarizations using a wire-grid polarizer. For waveguide dual polarization receivers, a moderately broadband septum ortho-mode transducer (OMT) is designed and experimental results are presented at millimeter wavelengths. Broadband finline OMTs are investigated for possible use at millimeter wavelengths, and experimental results of a finline OMT is presented at X-band.", "doi": "10.7907/RMVX-0619", "publication_date": "2000", "thesis_type": "phd", "thesis_year": "2000" }, { "id": "thesis:1596", "collection": "thesis", "collection_id": "1596", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-05032007-080831", "primary_object_url": { "basename": "Wong_jy_2000.pdf", "content": "final", "filesize": 22310563, "license": "other", "mime_type": "application/pdf", "url": "/1596/1/Wong_jy_2000.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Perpendicular patterned media for high density magnetic storage", "author": [ { "family_name": "Wong", "given_name": "Joyce Y.", "clpid": "Wong-J-Y" } ], "thesis_advisor": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" } ], "thesis_committee": [ { "family_name": "Scherer", "given_name": "Axel", "clpid": "Scherer-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Doll", "given_name": "Theodore", "clpid": "Doll-T" }, { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Current longitudinal thin-film media in magnetic hard-disk drives are facing an oncoming limit caused by the superparamagnetic effect, in which the individual grains in the medium become so small that they are no longer stable against thermal fluctuation. This situation is undesirable as the stored information may be lost within an unexpectedly short time frame. There have been several proposed solutions in addressing the superparamagnetic limit, and one of them is perpendicular patterned media. In this approach, a periodic array of magnetic pillars is defined lithographically on a non-magnetic substrate. Binary data of \"1\" or \"0\" can be stored in each of these elements, which have two possible magnetization directions perpendicular to the plane of the medium.\n\nIn our perpendicular patterned media design, Ni columns of 150-230nm diameter with a 6:1 aspect ratio are embedded in an (AlGa)2O3/GaAs substrate. The fabrication procedure uses a combination of high resolution electron beam lithography, dry etching, and electroplating. The high aspect ratio in the column is achieved by taking advantage of the high etching rate and selectivity of AlGaAs/GaAs over (AlGa)203 in the Cl2 chemically assisted ion beam etching process. In addition to being a robust etching mask, the (AlGa)2O3 layer also plays an important role in the chemical mechanical polishing procedure to remove the overplated Ni mushrooms.\n\nOnce the Ni columns are fabricated, magnetic characterization is performed using magnetic force microscopy and scanning magnetoresistance microscopy. The former measurement confirms that the electroplated Ni columns are magnetic while the latter determines whether the individual columns are stable enough to retain the recorded information. We have successfully demonstrated recording in our 170nm diameter Ni column array arranged in a square format using a commercial read/write head. This is the first demonstration of single magnetic column per bit data storage in a prototype perpendicular patterned medium. Furthermore, we have recorded in higher density Ni column arrays in the form of tracks, corresponding to 1.3 and 2.6Gbits/in.2. Even though we are limited by the spatial resolution of the magnetoresistive read sensor, we have continued to pursue higher density structures up to an areal density of 350Gbits/in.2. Consideration of the issues in high resolution patterning and the magnetic stability of the individual columns have prompted researchers in the magnetic recording industry to anticipate the ultimate storage limit of perpendicular patterned media to be around 1Tbits/in.2", "doi": "10.7907/WEP6-MN90", "publication_date": "2000", "thesis_type": "phd", "thesis_year": "2000" }, { "id": "thesis:60", "collection": "thesis", "collection_id": "60", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01072008-151023", "primary_object_url": { "basename": "Liu_c_1996.pdf", "content": "final", "filesize": 25011612, "license": "other", "mime_type": "application/pdf", "url": "/60/1/Liu_c_1996.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Silicon Micromachined Sensors and Actuators for Fluid Mechanics Applications", "author": [ { "family_name": "Liu", "given_name": "Chang", "clpid": "Liu-Chang" } ], "thesis_advisor": [ { "family_name": "Tai", "given_name": "Yu-Chong", "orcid": "0000-0001-8529-106X", "clpid": "Tai-Yu-Chong" } ], "thesis_committee": [ { "family_name": "Tai", "given_name": "Yu-Chong", "orcid": "0000-0001-8529-106X", "clpid": "Tai-Yu-Chong" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Antonsson", "given_name": "Erik K.", "clpid": "Antonsson-E-K" }, { "family_name": "Goodman", "given_name": "Rodney M.", "clpid": "Goodman-R-M" }, { "family_name": "Wu", "given_name": "Theodore Yao-tsu", "clpid": "Wu-T-Y-T" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The major contributions of this thesis are the developments of silicon micromachined flow shear-stress sensors and magnetic actuators, together with original studies on two fundamental issues of micro fabrication. Sensors and actuators applications in two fluid-mechanics projects have been successfully demonstrated.
\r\n\r\nMicro shear-stress sensors utilize boundary-layer thermal transfer principles. For the proposed fluid-mechanics applications these sensors must have higher sensitive compared with conventional sensors, among other requirements. This has been realized by implementing a unique vacuum-sealed cavity which greatly reduces heat loss to the substrate silicon.
\r\n\r\nFluid applications present unique challenges to micromachined actuators: they must achieve large out-of-plane motion and withstand large forces. We have developed two types of magnetic actuators that fit these requirements. The first type is based on interaction between the magnetic dipole moment of a current-carrying coil and an external magnetic field. A second-type uses the torque generated by an electroplated Permalloy (Ni[subscript 80]Fe[subscript 20] plate inside an external magnetic field.
\r\n\r\nThe two fundamental micro-fabrication issues are the reactive sealing of cavities and the magnetic-levitation assisted release of surface structures. We have conducted systematic experiments to determine the dependance of sealing performance on the test- structure geometric parameters, sealing materials and other factors. Release/drying of micro actuators, with their large surface areas, is especially challenging. The idea for magnetic-levitation assisted release is obtained while we were developing the Permalloy magnetic actuator. Magnetic forces counteract the surface tension forces during the drying to avoid structure stiction to the substrate. Original results from these fundamental studies add to the general micromachining knowledge base.
\r\n\r\nThe applications of developed sensors and actuators are demonstrated in two fluid- mechanics projects. In the first, we explore a unique scheme for active drag reduction, which is possible only by using a Micro Electro Mechanical System (MEMS). The MEMS consists of an array of shear-stress sensors, actuators and embedded neural-network (NN) circuitry. The goal of the second project is to achieve enhanced maneuverability of delta-wings using MEMS devices. Shear-stress sensors are successfully applied to identify the flow separation lines along the delta-wing's leading edges. Permalloy magnetic actuators interact with the leading-edge flow for controlling the wing motion.
", "doi": "10.7907/k8pm-8g13", "publication_date": "1996", "thesis_type": "phd", "thesis_year": "1996" }, { "id": "thesis:5050", "collection": "thesis", "collection_id": "5050", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-12182007-105428", "primary_object_url": { "basename": "Chiao_jc_1996.pdf", "content": "final", "filesize": 16166950, "license": "other", "mime_type": "application/pdf", "url": "/5050/1/Chiao_jc_1996.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Quasi-optical components for millimeter and submillimeter waves", "author": [ { "family_name": "Chiao", "given_name": "Jung-Chih", "clpid": "Chiao-J" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\n\nPower-combining schemes involving planar grids of solid-state devices or passive elements quasi-optically coupled in free space are an efficient means of combining power that makes them ideal for millimeter/submillimeter-wave applications by eliminating waveguide sidewall losses and machining difficulties. Three quasi-optical components including grid frequency multipliers, microswitch beam-steering grids and evanescent-wave couplers are presented.\n\nA terahertz grid frequency doubler using a 6x6 diode-grid periodically loaded with planar Schottky diodes has been developed. A peak output power of 330[...] was measured at 1.00 THz for 2.42-[...] 500-GHz input pulses with a peak power of 3.3 W.\n\nThe microswitch beam-steering grid has potential advantages over mechanical-scanning devices or active beam-steering reflectors based on diodegrids such as lower losses and simple control circuits at submillimeter wavelengths. Micromechanical electrostatically-controlled [...]-membrane switches have been fabricated on silicon wafers to provide binary reactance control. Simulations predict that a 4-bit controlled 10-layer microswitch beam-steering grid can have a phase-shift resolution of 22.5[...] over 360[...] with a maximum loss of 1.6 dB and a maximum phase error of 5[...] at 240 GHz.\n\nThe metal-mesh evanescent-wave couplers have been demonstrated to have wider bandwidths and larger modulations than Fabry-Perot couplers. The evanescent-wave coupling effect has been studied and used to increase the efficiency of an optically-controlled amplitude-modulator at 56.5 GHz.\n", "doi": "10.7907/qr6b-zk66", "publication_date": "1996", "thesis_type": "phd", "thesis_year": "1996" }, { "id": "thesis:13678", "collection": "thesis", "collection_id": "13678", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04202020-172701960", "type": "thesis", "title": "Measurement of the Leptonic Branching Fraction of the D\u209b Meson and Determination of Its Decay Constant", "author": [ { "family_name": "Kelsey", "given_name": "Michael Henderson", "clpid": "Kelsey-Michael-Henderson" } ], "thesis_advisor": [ { "family_name": "Hitlin", "given_name": "David G.", "clpid": "Hitlin-D-G" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Kavanagh", "given_name": "Ralph William", "clpid": "Kavanagh-R-W" }, { "family_name": "Porter", "given_name": "Frank C.", "clpid": "Porter-F-C" }, { "family_name": "Wise", "given_name": "Mark B.", "clpid": "Wise-M-B" }, { "family_name": "Hitlin", "given_name": "David G.", "clpid": "Hitlin-D-G" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "Between February 1992 and June 1994, the Beijing Spectrometer (BES) experiment collected 24.5 pb\u207b\u00b9 of data in e\u207ae\u207b collisions at a center of mass energy of 4.03 GeV, above threshold for production of D\u209b\u207aD\u209b\u207b meson pairs. In this thesis, these data are searched for D\u209b\u207aD\u209b\u207b events by identifying sets of charged tracks consistent with the decay channels D\u209b \u2192 \u03a6\u03c0,\u03a6 \u2192 K\u207aK\u207b; D\u209b \u2192 K*\u2070K,K*\u2070 \u2192 K\u207a\u03c0\u207b; or D\u209b \u2192 K\u2070SK,K\u2070S \u2192 \u03c0\u207a\u03c0\u207b. A global maximum-likelihood technique is used, which combines particle identification detector data and a kinematic fit to each decay hypothesis, for maximum sensitivity. A sample of 190 candidates is found in the mass range 1958.5-1978.5 MeV/c\u00b2, of which 76.9 \u00b1 13.8 are estimated (from a fit to 1097 combinations with 1800 < m < 2015 MeV /c\u00b2) to be true e\u207ae\u207b \u2192 D\u209b\u207aD\u209b\u207b events.
\r\n\r\nThis event sample is searched for leptonic decays of the D\u209b meson in the channels D\u209b \u2192 \u00b5\u03bd\u00b5 and D\u209b \u2192 \u03c4\u03bd\u03c4 (with \u03c4 \u2192 \u00b5\u03bd̅\u00b5\u03bd\u03c4 \u2192 e\u03bd̅e\u03bd\u03c4, or \u03c4 \u2192 \u03c0\u03bd\u03c4). Five candidate decays are found. A likelihood function is formed as a product over the candidate events, where each contributes a sum over all of the leptonic decay channels, weighted according to the likelihoods of the particle identifications and the kinematics of the decay. This likelihood function is maximized with respect to the branching fraction B(D\u209b \u2192 \u00b5\u03bd\u00b5), or the D\u209b pseudoscalar decay constant fD\u209b, with the results
\r\n\r\nB(D\u209b \u2192 \u00b5\u03bd\u00b5) = .75+1.23-.47 (stat) \u00b1 .06 (syst) %,
\r\nfD\u209b = 308+164-189 (stat) \u00b1 12 (syst) MeV.
\r\n\r\nComparison of the measured value of fD\u209b with other experimental determinations and with a variety of theoretical models is discussed, with implications for constraining those models.
", "doi": "10.7907/x5qg-g497", "publication_date": "1996", "thesis_type": "phd", "thesis_year": "1996" }, { "id": "thesis:4944", "collection": "thesis", "collection_id": "4944", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-12112007-082807", "primary_object_url": { "basename": "Raphaeli_d_1994.pdf", "content": "final", "filesize": 9455630, "license": "other", "mime_type": "application/pdf", "url": "/4944/1/Raphaeli_d_1994.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Noncoherent Coded Modulation", "author": [ { "family_name": "Raphaeli", "given_name": "Dan", "clpid": "Raphaeli-Dan" } ], "thesis_advisor": [ { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" } ], "thesis_committee": [ { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Simon", "given_name": "Marvin K.", "clpid": "Simon-M-K" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "In this thesis, we are concerned with the transmission of data over noncoherent channels (the carrier phase is random). We consider a receiving system which does not attempt to estimate the carrier phase from the received data. Instead, the transmitter and receiver will be designed so that the data transmission is robust with respect to the unknown phase variations of the channel. For the transmitter, we propose new combined coding and modulation, specifically designed to match the noncoherent channel. For the receiver, efficient decoders to noncoherently decode the coded modulation are developed. As a result, we are able to show, both analytically and by computer simulations, that Noncoherent Coded Modulation (NCM) approaches the performance of coded coherent modulation. NCM achieves almost the same power efficiency without bandwidth expansion or an extensive increase in complexity.
\r\n\r\nWe consider the problem of the Uniform Error Property (UEP) for a broad class of transmitters and receivers. A sufficient condition for a general linear code to satisfy the UEP is presented and a structure of a trellis-coded modulation that satisfies this condition is offered. We call these codes \"linear noncoherent trellis-coded modulation\" since they apply to noncoherent detection. The problem of noncoherently catastrophic codes, which can result in noncoherent detection of trellis codes, is discussed and a general solution which does not rely on differential encoding of the code output is offered.
\r\n\r\nHigh performance noncoherent detection is achieved using multiple symbol observations. Unlike previous approaches, a sliding window is used for the observations, with each observation covering several branches of the trellis, so that the observations are time-overlapped. We define a new type of noncoherent maximum likelihood sequence estimator, and analyze its performance over the Additive White Gaussian Noise (AWGN) channel by numerical calculation of the union bound. We perform a computerized search and present new high performance coded M-ary Phase Shift Keying (PSK) modulations for noncoherent detection and their performance. The new codes cover many useful rates and complexities and achieve higher performance than existing codes for noncoherent detection. We evaluate the performance of NCM in the presence of phase jitter in the channel. The method can also be used for multiple symbol demodulation of M-ary Differential PSK (MDPSK) and of Continuous Phase Modulation (CPM). We provide results for both, full and partial response CPM schemes as well as convolutionally coded CPM. The complexity and power efficiency of this new method is superior to all past schemes known to the author for noncoherent detection.
\r\n\r\nThe optimal implementation of the decoder, using the Viterbi Algorithm (VA), is given. For L-symbols observation, it requires a number of states that grows exponentially with L. Three novel sub-optimal algorithms are presented, whose number of states is the same as the original code so their complexity has a relatively weak dependence on L. For practical values of L, these algorithms are substantially less complex than the optimal algorithm.
\r\n\r\nThe first suboptimal algorithm to be described is called the Basic Decision Feedback Algorithm (BDFA). In this algorithm, the symbols from the decisions are fed back to be used in the subsequent decisions. This algorithm suffers from increased error event probability and from error propagation. However, by a small modification of the BDFA, we obtain another improved algorithm, which will be called Modified Decision Feedback Algorithm (MDFA).
\r\n\r\nTo obtain close to optimal performance, the third algorithm, the Estimated Future Decision Feedback Algorithm (EFDFA) is offered. This sophisticated algorithm, which uses the BDFA as a basic building block, is based on a novel concept called \"estimated future.\" Performance analysis and simulation results are given.
", "doi": "10.7907/fexw-ex94", "publication_date": "1994", "thesis_type": "phd", "thesis_year": "1994" }, { "id": "thesis:4975", "collection": "thesis", "collection_id": "4975", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-12122007-135636", "primary_object_url": { "basename": "Antsos_d_1994.pdf", "content": "final", "filesize": 10519161, "license": "other", "mime_type": "application/pdf", "url": "/4975/1/Antsos_d_1994.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Computer-aided modeling and analysis of passive microwave and millimeter-wave high-temperature superconductor circuits and components", "author": [ { "family_name": "Antsos", "given_name": "Dimitrios", "clpid": "Antsos-D" } ], "thesis_advisor": [ { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" } ], "thesis_committee": [ { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" }, { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "As their critical temperatures continue to rise, high-temperature superconductors (HTS) promise applications in microwave, and to some extent in millimeter-wave circuits, because they should exhibit lower loss, in these frequencies, than their normal metal counterparts. However, in the case of passive circuits, fundamental performance limits (finite insertion loss) still exist and apply, as explored in this thesis.\n\nCommercial computer-aided design (CAD) and analysis software tools exist, that permit design and analysis of normal metal microwave and millimeter-wave circuits. These tools minimize design and manufacturing errors and the need for costly re-work and design iterations. In the case of HTS circuits these tools are insufficient because of three effects present in HTS circuits that do not exist in normal metal circuits. First, because of manufacturing practices, the HTS layers on substrates are usually very thin; of the order of the magnetic field penetration depth. Second, there is an additional internal inductance, the kinetic inductance, which is due to the inertia of the superelectrons. Third, high input power induces high magnetic fields and current densities which drive the superconductor into its normal state, in which it is an insulator.\n\nThis thesis is a study of these phenomena and their effects on quasi-TEM transmission line circuit performance. Methods for accounting for these effects and introducing them into currently available CAD tools are presented. These methods are applied to three example circuits for which modeled and measured performance is compared.\n\nThe viability and advantages of HTS waveguides are also studied and analyzed. A finite difference analysis program is presented.", "doi": "10.7907/fb3q-7f74", "publication_date": "1994", "thesis_type": "phd", "thesis_year": "1994" }, { "id": "thesis:2956", "collection": "thesis", "collection_id": "2956", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-07202007-143215", "primary_object_url": { "basename": "c_ji_1992.pdf", "content": "final", "filesize": 3934938, "license": "other", "mime_type": "application/pdf", "url": "/2956/1/c_ji_1992.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Generalization capability of neural networks", "author": [ { "family_name": "Ji", "given_name": "Chuanyi", "clpid": "Ji-Chuanyi" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Goodman", "given_name": "Rodney M.", "clpid": "Goodman-R-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The generalization capability of feedforward multilayer neural networks is investigated from two aspects: the theoretical aspect and the algorithmic aspect.
\r\n\r\nIn the theoretical part, a general relation is derived between the so-called VC-dimension and the statistical lower epsilon-capacity, and then applied to two cases. First, as a general constructive approach, it is used to evaluate a lower bound of the VC-dimension of two layer networks with binary weights and integer thresholds. Second, how the sample complexity may vary with respect to distributions is investigated through analyzing a particular network which separates two binary clusters. Bounds for the capacity of two layer networks with binary weights and integer thresholds are also obtained.
\r\n\r\nIn the algorithmic part, a network reduction algorithm is developed to study generalization in learning analog mappings. It is applied to control a two-link manipulator to draw characters. The network addition-deletion algorithm is described to find an appropriate network structure during learning. It is used to study the effect of sizes of networks on generalization, and applied to various classification problems including hand written digits recognition.
", "doi": "10.7907/HR3F-0410", "publication_date": "1992", "thesis_type": "phd", "thesis_year": "1992" }, { "id": "thesis:3146", "collection": "thesis", "collection_id": "3146", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08162007-095038", "primary_object_url": { "basename": "Weikle_rm_1992.pdf", "content": "final", "filesize": 6979106, "license": "other", "mime_type": "application/pdf", "url": "/3146/1/Weikle_rm_1992.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Quasi-optical planar grids for microwave and millimeter-wave power combining", "author": [ { "family_name": "Weikle", "given_name": "Robert M.", "clpid": "Weikle-R-M" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Frerking", "given_name": "Margaret", "clpid": "Frerking-M" }, { "family_name": "Itoh", "given_name": "Tatsuo", "clpid": "Itoh-T" } ], "abstract": "Solid-state devices that produce radiation in the microwave and millimeter-wave region of the electromagnetic spectrum have relatively low power outputs compared to their electron-tube counterparts. In an attempt to obtain more power from solid-state sources, a number of power-combining schemes have been developed through the years. One of the most promising techniques involves superposing the outputs of many devices in free space. This quasi-optical approach has several advantages: the losses associated with waveguides and feed networks are eliminated, the power can be distributed over a large number of devices, and an external phase-locking signal is unnecessary. In this work, a method for quasi-optical power combining which is based on integrating devices into periodic grids is discussed. The approach is relatively simple to implement because the grid structures are planar. Thus they easily accommodate solid-state devices and allow for the possibility of wafer-scale integration. A method for analyzing the grids is presented and used to derive models for a variety of configurations. The validity of these models is investigated using a quasi-optical reflectometer. Designs and experimental results for MESFET oscillator grids operating in X-band and Ku-band are examined and discussed in detail.", "doi": "10.7907/K6WY-6V76", "publication_date": "1992", "thesis_type": "phd", "thesis_year": "1992" }, { "id": "thesis:3039", "collection": "thesis", "collection_id": "3039", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08072007-133843", "primary_object_url": { "basename": "Lin_sh_1992.pdf", "content": "final", "filesize": 10394982, "license": "other", "mime_type": "application/pdf", "url": "/3039/1/Lin_sh_1992.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "GaAs optoelectronic integrated circuits for optical neural network applications", "author": [ { "family_name": "Lin", "given_name": "Steven H.", "clpid": "Lin-S-H" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optoelectronic integrated circuits (OEIC's) have emerged as a viable method in the implementation of optical neurons required for a neural network. This is due to the increased capability in both the material and the device engineering in GaAs technology, which has proliferated incredibly fast during the last decade. In this thesis, two different approaches to monolithically integrate various electronic and optical devices are explored for the implementation of optical neurons. The first approach utilizes the technology from double heterojunction bipolar transistor for its potentially high current gain and its structural compatibility with optical devices. In achieving the current gain required for optical neurons, modeling of the base leakage current, effect of surface passivation and diffusion characteristics is performed for Zn-diffused bipolar transistors. The second approach employs metal semiconductor field-effect transistors as the driver for the optical devices. It is found that, by properly designing the circuit, high optical gain, low electrical power dissipation and low optical switching energy thresholding devices can be accomplished in this approach with large input-output isolation. Such performance is required if large arrays of optoelectronic neurons are to be inserted into a neural network to perform tasks that make neural computation a unique approach in solving a certain class of problems. In this thesis, an optical gain of 80 is demonstrated along with an electrical power dissipation of 1.6 mW and an optical switching energy of 10 pJ. These results generate high promises and optimism for the realization of a physical neural computer in the near future.", "doi": "10.7907/tqm4-en29", "publication_date": "1992", "thesis_type": "phd", "thesis_year": "1992" }, { "id": "thesis:3581", "collection": "thesis", "collection_id": "3581", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09172003-101254", "primary_object_url": { "basename": "Wedge_sw_1991.pdf", "content": "final", "filesize": 3121197, "license": "other", "mime_type": "application/pdf", "url": "/3581/1/Wedge_sw_1991.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Computer-aided design of low noise microwave circuits", "author": [ { "family_name": "Wedge", "given_name": "Scott William", "clpid": "Wedge-S-W" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Elachi", "given_name": "Charles", "clpid": "Elachi-C" }, { "family_name": "Zmuidzinas", "given_name": "Jonas", "clpid": "Zmuidzinas-J" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" }, { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Devoid of most natural and manmade noise, microwave frequencies have detection sensitivities limited by internally generated receiver noise. Low-noise amplifiers are therefore critical components in radio astronomical antennas, communications links, radar systems, and even home satellite dishes. A general technique to accurately predict the noise performance of microwave circuits has been lacking. Current noise analysis methods have been limited to specific circuit topologies or neglect correlation, a strong effect in microwave devices. Presented here are generalized methods, developed for computer-aided design implementation, for the analysis of linear noisy microwave circuits comprised of arbitrarily interconnected components. Included are descriptions of efficient algorithms for the simultaneous analysis of noisy and deterministic circuit parameters based on a wave variable approach. The methods are therefore particularly suited to microwave and millimeter-wave circuits. Noise contributions from lossy passive components and active components with electronic noise are considered. Also presented is a new technique for the measurement of device noise characteristics that offers several advantages over current measurement methods.", "doi": "10.7907/ZRTG-GX48", "publication_date": "1991", "thesis_type": "phd", "thesis_year": "1991" }, { "id": "thesis:4463", "collection": "thesis", "collection_id": "4463", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-11082007-105043", "primary_object_url": { "basename": "Sivarajan_kn_1990.pdf", "content": "final", "filesize": 3097788, "license": "other", "mime_type": "application/pdf", "url": "/4463/1/Sivarajan_kn_1990.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Spectrum efficient frequency assignment for cellular radio", "author": [ { "family_name": "Sivarajan", "given_name": "Kumar N.", "clpid": "Sivarajan-K-N" } ], "thesis_advisor": [ { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" } ], "thesis_committee": [ { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Franklin", "given_name": "Joel N.", "clpid": "Franklin-J-N" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\n\nIn this thesis, we first describe some results on the following generalized chromatic number problem that has its origin in cellular radio (the frequency assignment problem with co-channel constraints only): Given a graph G with vertices V = [...] and an n-vector M = [...] of nonnegative integers (the requirement vector), find the minimum number of colors, [...](G, M), required to assign [...] distinct colors to vertex [...], [...], such that adjacent vertices are assigned disjoint sets of colors. We develop a lower bound on [...](G, M), which generalizes and strengthens the well-known bound [...] n for the usual chromatic number. We show that this bound is sharp for a number of interesting graphs (e.g., perfect graphs and odd cycles), but not for all graphs - the Grotzsch graph being a counterexample. We also give examples of the application of this bound to frequency assignment in cellular radio.\n\nIn the presence of constraints other than just co-channel constraints (e.g., adjacent channel and co-site constraints), the frequency assignment problem is a further generalization of the graph coloring problem. We describe some heuristic algorithms for frequency assignment in cellular radio that we developed by suitably adapting some of the ideas previously introduced in heuristic graph coloring algorithms. These algorithms have yielded optimal, or near-optimal assignments, in many cases.\n\nWe then describe some dynamic channel assignment algorithms for cellular systems that we have developed. In addition to having a considerable advantage over fixed channel assignment in the range of blocking probabilities of interest in current cellular systems (2-4%), these algorithms are feasible for implementation in these systems. Some of these dynamic channel assignment algorithms are also shown to give good performance under overload (heavy traffic conditions).\n\nFinally, we discuss various methods of computing interference probabilities and the formulation of compatibility constraints on channel assignment based on these calculations. We also formulate the channel assignment problem as one of coloring hypergraphs, instead of graphs, and show that, in the case of dynamic channel assignment, this leads to a considerable increase in the carried traffic for the same blocking probability and the same maximum probability of interference.", "doi": "10.7907/q2qb-hh14", "publication_date": "1990", "thesis_type": "phd", "thesis_year": "1990" }, { "id": "thesis:553", "collection": "thesis", "collection_id": "553", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02082007-125156", "type": "thesis", "title": "Theory and Experiments on Unstable-Resonator and Quantum Well GaAs/GaAlAs Lasers", "author": [ { "family_name": "Mittelstein", "given_name": "Michael", "clpid": "Mittelstein-Michael" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Culick", "given_name": "Fred E. C.", "clpid": "Culick-F-E-C" }, { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" }, { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Structures of GaAs/GaA1As lasers and their performance characteristics are investigated experimentally and theoretically. A self-consistent model for the longitudinal gain and intensity distribution in injection lasers is introduced. The model is applied to unstable-resonator semiconductor lasers to evaluate their lateral losses and quantum efficiencies, and an advanced design is presented. Symmetric, unstable-resonator semiconductor lasers are manufactured and a virtual source point inside the laser more than an order of magnitude narrower than the width of the near field is demonstrated. Young's double-slit experiment is adopted for lateral coherence measurements in semiconductor lasers. A high degree of lateral coherence is found, indicating operation of the unstable-resonator lasers in predominantly one mode.
\r\n\r\nIn the pulsed measurements on broad-area, single-quantum-well, graded-index wave-guide, separate-confinement-heterostructure lasers, very high quantum efficiencies, very low losses, and very high output powers are observed. The devices are found to exhibit beam divergence narrower than two times the diffraction limit in single-lobed, far-field patterns. Using these single-quantum-well lasers, the \"second quantized-state lasing\" is found experimentally, and a simple model is developed to explain it.
\r\n\r\nA general model for the gain spectrum and required current density of quantum-well lasers is introduced. The eigenfunctions and eigenvalues of the charge carriers and optical mode of the transverse structure are used to derive the gain spectrum and current density from the Einstein coefficients. The two-dimensional density of states for the charge carriers and the effective width of the optical mode (not the width of the quantum well) are identified as the dominant parameters. The model includes a new heuristic approach to account for the observed smeared onset of subbands, eliminating convolution calculations.
\r\n\r\nApplications of the model for a typical structure, a conventional double heterostructure and an advanced structure are presented. Structures providing two- and three-dimensional confinement are discussed and are directly compared to conventional and quantum-well structures in terms of laser parameters. The length scale of confinement structures for the optical mode is found to be two orders of magnitude larger than the corresponding length scale for carrier confinement, implying that the single-quantum-well laser is the most adapted structure.
\r\n\r\nThe gain-flattened condition that single-quantum-well lasers exhibit near the onset of the second quantized-state lasing is introduced. An external grating-tuned resonator is analyzed, and the coupled cavity formalism is employed to examine conditions for continuous tuning. Predictions for tuning ranges of conventional, double-heterostructure and single-quantum-well lasers are made, and the superiority of the latter on account of pump current density is clarified. Experimentally, broadband tunability exceeding a 10% spectral tuning range of an uncoated quantum-well laser in a simple grating-tuned resonator is demonstrated.
", "doi": "10.7907/p3k2-pp58", "publication_date": "1989", "thesis_type": "phd", "thesis_year": "1989" }, { "id": "thesis:646", "collection": "thesis", "collection_id": "646", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02162007-080706", "type": "thesis", "title": "Computer-Aided Measurement of Microwave Circuits", "author": [ { "family_name": "Williams", "given_name": "Wyman Lee", "clpid": "Williams-Wyman-Lee" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Instruments that measure the scattering parameters of microwave circuits generally have large systematic errors due to unavoidable parasitics in the instruments. These errors can be modeled analytically, however, and removed through a calibration procedure. A personal computer is well suited to the performance of the required calculations. Combining a personal computer with a microwave network analyzer results in a flexible and accurate automatic instrument. Two such automatic network analyzers are presented here. A new type of network analyzer, known as a sampled-line network analyzer is presented. It is an extension of the six-port network analyzer concept developed at the National Bureau of Standards. It is a particularly simple implementation and shows promise for the construction of relatively low-cost microwave network analyzers. The sampled-line network analyzer is analyzed theoretically and several experimental versions of it are presented. Another personal computer-controlled network analyzer is presented in which a Pascal program automates an HP 8410 network analyzer. The result is an instrument which can measure S-parameters from 0.5 to 18 GHz with a measurement error vector ranging in magnitude from 0.01 in the low frequency range to about 0.03 at 18 GHz.
", "doi": "10.7907/65XX-PQ66", "publication_date": "1989", "thesis_type": "phd", "thesis_year": "1989" }, { "id": "thesis:4464", "collection": "thesis", "collection_id": "4464", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-11082007-111802", "type": "thesis", "title": "Monolithic Millimeter-Wave Two-Dimensional Horn Imaging Arrays", "author": [ { "family_name": "Rebeiz", "given_name": "Gabriel M.", "clpid": "Rebeiz-Gabriel-M" } ], "thesis_advisor": [ { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Elachi", "given_name": "Charles", "clpid": "Elachi-C" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Fetterman", "given_name": "Harold", "clpid": "Fetterman-Harold" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "A new monolithic millimeter-wave two-dimensional horn imaging array is presented. In this configuration, a dipole is suspended in an etched pyramidal cavity on a 1-\u00b5m silicon-oxynitride membrane. This approach allows ample space for low-frequency interconnections, while still maintaining efficient diffraction-limited imaging. The fabrication procedure of the horn array and the deposition parameters of the membrane layer are presented in detail. The array is analysed rigorously, by approximating the horn antenna by a structure of multiple rectangular waveguide sections. Pattern measurements at 93 GHz and 242 GHz agree well with the theory. The results show that horn antennas with an opening between 1.0\u03bb and 1.5\u03bb have high aperture efficiencies and would match well appropriate imaging systems. Also, a new wideband log-periodic antennas is integrated on a thin membrane and tuned by a back plane reflector. The antenna patterns are measured at 167 GHz, 370 GHz and 700 GHz, and the effect of the back-plane reflector is investigated at 370 GHz.
", "doi": "10.7907/B9FG-6H18", "publication_date": "1988", "thesis_type": "phd", "thesis_year": "1988" }, { "id": "thesis:4478", "collection": "thesis", "collection_id": "4478", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-11092007-084226", "type": "thesis", "title": "Neuron-Microdevice Connections", "author": [ { "family_name": "Regehr", "given_name": "Wade Gordon", "clpid": "Regehr-Wade-Gordon" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Bellan", "given_name": "Paul Murray", "clpid": "Bellan-P-M" }, { "family_name": "Lester", "given_name": "Henry A.", "clpid": "Lester-H-A" }, { "family_name": "Bower", "given_name": "James M.", "clpid": "Bower-J-M" }, { "family_name": "Pine", "given_name": "Jerome", "clpid": "Pine-J" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "A new method for long-term recording and stimulation applicable to cultured neurons has been developed. Silicon-based microelectrodes have been fabricated using integrated-circuit technology and micromachining. The chronic connection is made by positioning the electrode tip into contact with the cell body, and gluing the device to the bottom of the culture dish. These \"diving-board electrodes\" consist of an insulated lead exposed only at the tip sealed to the cell body of a cultured neuron. A two-way electrical connection to Helisoma B19 neurons has been established for up to four days. Preliminary experiments with cultured superior cervical ganglion neurons indicate diving-board electrodes can be used with cultured neurons larger than 20 \u00b5m in diameter.
\r\n\r\nIn a related technique Helisoma neurons grown on special dish containing a multielectrode array were found to seal to the dish electrodes, establishing similar long-term connections. This capability will make it possible to conduct experiments with either diving-board electrodes or dishes that cannot be performed using conventional techniques.
", "doi": "10.7907/nshf-ww49", "publication_date": "1988", "thesis_type": "phd", "thesis_year": "1988" }, { "id": "thesis:435", "collection": "thesis", "collection_id": "435", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02012007-084647", "type": "thesis", "title": "Heterodyne Detection with Superconducting Tunnel Diodes", "author": [ { "family_name": "Wengler", "given_name": "Michael James", "clpid": "Wengler-Michael-James" } ], "thesis_advisor": [ { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" } ], "thesis_committee": [ { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Johnson", "given_name": "William Lewis", "clpid": "Johnson-W-L" }, { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Vahala", "given_name": "Kerry J.", "clpid": "Vahala-K-J" } ], "local_group": [ { "literal": "Astronomy Department" }, { "literal": "div_eng" } ], "abstract": "Heterodyne receivers based on superconductor-insulator-superconductor (SIS) tunnel diodes are the most sensitive available for near-millimeter wavelengths. Since the late seventies, receivers based on SISs have been used for millimeter band observations at radio observatories around the world. The work described here was carried out with the elusive goal in mind of developing ideal SIS receivers for radioastronomy. This thesis describes one researcher's path towards this goal.
\r\n\r\nIn the first chapter, a basic description of SIS diodes, their interaction with radiation, and heterodyne detection are given. The important detailed results of J. R. Tucker's tunnel diode heterodyne theory are described, since subsequent chapters rely on Tucker's work quite heavily. Throughout this introductory chapter, extremely simple (by comparison with the algebraic theoretical results) physical models are used to describe superconductivity, SISs, photon-assisted tunneling, and heterodyne detection. It is the author's experience that these physical models can be used to derive correct theoretical results, long before these results are proved rigorously.
\r\n\r\nThe second chapter presents a fully quantum mechanical theory of heterodyne detection with diodes. This theory was developed because Tucker's theory for tunnel diodes predicts a greater mixer sensitivity than is possible considering Heisenberg's uncertainty principle for radiation. Tucker does not quantize the radiation incident on the SIS, although his treatment of the isolated tunnel diode is completely quantum mechanical. In chapter 2, the quantization of radiation is carried out for heterodyne diode detectors. The formalism is shown to obey quantum limits on sensitivity. Finally, an ideal SIS mixer is shown to have noise properties identical to those of optical mixers based on ideal photodiodes.
\r\n\r\nIn possession of an apparently complete theory for SIS mixers, the third chapter presents a sampling of numerical results from that theory. Four different non-ideal tunnel diodes are used for these calculations so that a quantitative feel for the importance of diode quality can be achieved. The effects of dc and LO bias, signal and image source admittance, frequency of operation, and junction quality are all explored. This information will be useful for the proper engineering of SIS mixers. Finally, the fully optimized performance of the four tunnel diodes is presented as frequency is varied. It is shown that reasonably good quality lead-alloy SISs should behave like photodiodes up to frequencies as high as 1500 GHz.
\r\n\r\nFinally, chapter 4 presents a prototype open-structure SIS mixer. Measurements in the laboratory show this mixer to be quite sensitive for signal frequencies from 115 to 761 GHz. Unlike all other SIS receivers, in which the diode is mounted across a waveguide, this mixer relies on the bowtie-on-quartz antenna structure, which has been investigated by D. B. Rutledge and his students. This difference is essential to the multi-octave spectral coverage of this mixer. It is probable that waveguide designs will never achieve good results above 500 GHz, and as of now, there are no SIS-waveguide mixers which operate well above 300 GHz. Tests at the Owens Valley Radio Observatory verify the suitablility of this mixer for radioastronomy, but these tests have been limited to frequencies of 260 GHz and lower.
", "doi": "10.7907/TYQQ-RZ71", "publication_date": "1988", "thesis_type": "phd", "thesis_year": "1988" }, { "id": "thesis:3696", "collection": "thesis", "collection_id": "3696", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09222006-130413", "type": "thesis", "title": "I. A Unified Analysis of Converters with Resonant Switches. II. Input-Current Shaping for Single-Phase Ac-Dc Power Converters", "author": [ { "family_name": "Freeland", "given_name": "Stephen D.", "clpid": "Freeland-Stephen-D" } ], "thesis_advisor": [ { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" } ], "thesis_committee": [ { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" }, { "family_name": "Beck", "given_name": "James L.", "clpid": "Beck-J-L" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Part I:
\r\n\r\nQuasi-resonant converters are a family of single-switch resonant dc-dc converters featuring zero-current or zero-voltage switching. Recognition of the topological structure uniting these resonant converters--and the rectangular-wave (PWM) converters on which they are based--leads to general models of their dc and low-frequency ac behavior.
\r\n\r\nAn expression is derived that yields the dc conversion ratio of a quasi-resonant converter in terms of the well-known conversion ratio of the underlying PWM topology. A small-signal, low-frequency dynamic model is developed whose parameters also incorporate the PWM conversion ratio. The dc and ac models reveal that any quasi-resonant converter with a full-wave resonant switch has dc and low-frequency behavior identical to that of its PWM parent, with switching-frequency control replacing duty-ratio control. Converters with half-wave resonant switches behave more like PWM converters in discontinuous conduction mode or with current programming, exhibiting lossless damping in the small-signal model and output resistance at dc.
\r\n\r\nAlthough quasi-resonant converters come in an astounding variety of topologies, the dc (and to a large extent ac) behavior of these converters depends only on the underlying PWM topology and the class of resonant switch, and is unchanged by movement of the resonant reactances to various alternative positions.
\r\n\r\nPart 2:
\r\n\r\nThe distorted input-current waveforms of nonlinear electronic loads cause interference and lead to poor utilization of the utility power line, a situation that is rapidly becoming intolerable with the increased application of electronic loads. Input-current shaping, also known as power-factor improvement, addresses the problem of improving current waveforms drawn from the power line. This study is restricted to single-phase ac-dc power conversion systems.
\r\n\r\nCurrent-shaping circuits are shown to fall into just a few categories with common features and limitations. In addition to the more common buck- and boost-based current-shaping converters, a class of circuits with \"automatic\" current shaping is presented and analyzed. A set of rules is derived for determining whether a particular dc-dc converter topology is suitable for use as a current-shaping ac-dc converter, and the rules are used to judge the suitability of several resonant converter topologies for this application. A new, low-cost converter is suggested that combines input-current shaping, isolation, and fast output-voltage regulation.
\r\n\r\nInput-current shaping requires that a converter store significant energy, leading to unfortunate size and weight restrictions. Additional implications of stored energy are examined, along with several methods of reducing the energy storage. It is shown that the ability of a current-shaping converter to regulate its output voltage is severely restricted as a result of the energy requirement. The methods and implications of introducing isolation to a shaping ac-dc converter are also studied.
", "doi": "10.7907/PVNN-X318", "publication_date": "1988", "thesis_type": "phd", "thesis_year": "1988" }, { "id": "thesis:7424", "collection": "thesis", "collection_id": "7424", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:01222013-150156111", "type": "thesis", "title": "A Far-Infrared Heterodyne Spectrometer for Airborne Astronomy", "author": [ { "family_name": "Grossman", "given_name": "Erich Nathan", "clpid": "Grossman-Erich-Nathan" } ], "thesis_advisor": [ { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" } ], "thesis_committee": [ { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Cross", "given_name": "Michael Clifford", "clpid": "Cross-M-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Kulkarni", "given_name": "Shrinivas R.", "clpid": "Kulkarni-S-R" } ], "local_group": [ { "literal": "Caltech Submillimeter Observatory" }, { "literal": "Astronomy Department" }, { "literal": "div_pma" } ], "abstract": "The design and construction of a novel heterodyne spectrometer for airborne astronomy in the 50 \u00b5m - 200 \u00b5m wavelength range is described. along with laboratory measurements of its performance. A bulk, extrinsic Ge:Ga photoconductor is used as the mixer. Its low bandwidth, determined by the hole recombination rate, necessitates the use of a continuously tunable local oscillator. This is provided by a far-infrared laser sideband generator, which is based on a GaAs Schottky diode mounted at the feed of a comer-cube antenna, the latter combination acting as a reflective FIR modulator.
\r\n\r\nThe first chapter of this thesis describes the astronomical and technical context of the project - in particular, the constraints which the astronomical goals set on the instrument, and the advantages and drawbacks of each of the various broad instrumental strategies that are available for spectrometer design. The chapter's last section provides a very brief overview of our most successful laboratory results, which are described at greater length in chapters 2- 4. In chapter two we describe the performance of Ge:Ga mixers as heterodyne mixers. We report on an extensive series of measurements of bandwidth, photoconductive gain, and direct detection responsivity for a series of highly compensated, NTD detectors grown specifically for this purpose. Chapter two also describes a nunber of experiments on FIR heterodyne performance, made using the direct, attenuated laser, rather than the output of the sideband generator, as the local oscillator. These confirm the expectation that germanium photoconductors are capable of quantum-limited noise performance with quantum efficiencies of ~10%, at much lower LO powers than required for Schottky diodes. Our best achieved noise temperature is TN(DSB) = 655K at PLO = 1.6\u00b5W, a factor of > 25 lower than the best reported corresponding figure for Schottky diodes.
\r\n\r\nChapter 3 describes the operating principles and construction of our FIR laser, which formed a basic tool in nearly all our laboratory experiments. A brief discussion of the Lorenz instability in FIR lasers is also given, in connection with various observations we have made of spontaneous pulsations and excess low-frequency noise on the laser output, and which have recently been the subject of considerable study by other researchers. Chapter four describes FIR laser sideband generation using small-area Schottky diodes and comer-cube antennas. The construction and performance of our corner-cubes is outlined, including the first direct measurement of the main beam efficiency of a corner-cube antenna in the FIR, and a comparison with theory. The construction and measured performance of the rest of the sideband generator is also described. A detailed, quantitative model has been developed for the conversion efficiency obtainable from Schottky diodes in this application. We find that the low conversion efficiency (-39 db) measured in our experiments, and comparable to that found by other researchers, is inherent in the diode and well predicted by the model. For our particular experiment, the model predicts -28 db loss due to the diode, plus approximately -10 db loss due to the antenna coupling efficiency. The dependence of conversion efficiency on diode parameters is studied and guidelines for future optimization derived. Unfortunately, the severe conversion loss we measure, combined with low FIR laser power and (somewhat less significantly) poor optics transmission, leads to our presently available LO power being inadequate to obtain astronomically useful sensitivity, by a large factor.
", "doi": "10.7907/79cv-bm83", "publication_date": "1988", "thesis_type": "phd", "thesis_year": "1988" }, { "id": "thesis:439", "collection": "thesis", "collection_id": "439", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02012007-110846", "type": "thesis", "title": "Diffusion Barriers for VLSI Applications", "author": [ { "family_name": "So", "given_name": "Frank Cheung Tao", "clpid": "So-Frank-Cheung-Tao" } ], "thesis_advisor": [ { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" } ], "thesis_committee": [ { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" }, { "family_name": "Fultz", "given_name": "Brent T.", "orcid": "0000-0002-6364-8782", "clpid": "Fultz-B-T" }, { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" }, { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis is concerned with diffusion barriers in contact structures to semiconductors. Diffusion barriers are indispensable in present contact technologies to preserve device characteristics from the influence of metal-semiconductor interaction during post-metallization processing.
\r\n\r\nThe absence of grain boundaries makes amorphous W-Zr and Ni-W alloy barriers very attractive for high temperature applications. Nevetheless, in the presence of an adjoining metal layer such as Al, these amorphous barriers are chemically dissociated to form compounds with the metal. The usefulness of these barrier in VLSI metallization schemes is severely limited by their high reactivity with Al within normal processing temperature cycles. Such thermal instability can be removed, however, by adding nitrogen to the barrier layers during sputter deposition.
\r\n\r\nBecoming aware of the beneficial effects of nitrogen incorporation, we investigate the performance of nitrogen-doped W barrier films in various contact configurations. Reactively sputtered amorphous and polycrystalline W-N layers are demonstrated to be excellent diffusion barriers against interdiffusion between Si-Al, Si-Ag, GaAs-Ag, and GaAs-Au. A novel idea of utilizing W-N as an interconnect in CMOS fabrication is also discussed.
\r\n\r\nConducting transition metal oxides emerge as a new class of diffusion barriers. Metallic Mo1-xOx films are deposited by reactive sputtering a Mo target in controlled O\u2082/Ar ambients. These Mo1-xOx barriers can effectively protect Si n\u207a-p shallow junctions from Al spiking even beyond the eutectic temperature of Si-Al. RuO\u2082 films are also found to be equally good in suppressing Si-Al interdiffusion. The present study clearly shows that Mo1-xOx and RuO\u2082 barriers are the most outstanding performers among all the passive barriers that have been explored so far.
", "doi": "10.7907/7ytp-0932", "publication_date": "1988", "thesis_type": "phd", "thesis_year": "1988" }, { "id": "thesis:815", "collection": "thesis", "collection_id": "815", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02282008-135956", "primary_object_url": { "basename": "Compton_rc_1987.pdf", "content": "final", "filesize": 10157731, "license": "other", "mime_type": "application/pdf", "url": "/815/1/Compton_rc_1987.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Analysis of Millimeter and Microwave Integrated Circuits", "author": [ { "family_name": "Compton", "given_name": "Richard C.", "clpid": "Compton-Richard-C" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "McEliece", "given_name": "Robert J.", "clpid": "McEliece-R-J" }, { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Pickett", "given_name": "Herbert M.", "clpid": "Pickett-H-M" }, { "family_name": "Alexopoulos", "given_name": "Nicolaos G.", "clpid": "Alexopoulos-Nicolaos-G" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The design and measurement of millimeter and microwave integrated circuits encompasses a diverse spectrum of interesting disciplines. A number of contrasting approaches used for theoretically and experimentally characterizing circuits in this frequency range will be presented. Rigorous methods for calculating antenna patterns and impedances of the planar bow-tie antenna used in millimeter wave receiver systems have been developed. A 94 GHz antenna measurement system and microwave scale models were constructed to confirm these theoretical predictions. Pattern measurements were also made on a linear array of bow-tie antennas, a long strip antenna, and a log-periodic antenna. In modified form, these techniques were applied to the investigation of planar array structures. An equivalent circuit model for an array of squares joined at the corners by discrete devices was formulated. This model was verified with impedance and pattern measurements. Finally, a set of analysis tools that have been assembled into an interactive computer-aided design program, called Puff, is discussed. Puff has been used in microwave laboratory classes at the California Institute of Technology, Cornell University and the University of California, Los Angeles.
\r\n", "doi": "10.7907/P7EA-S138", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:856", "collection": "thesis", "collection_id": "856", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03032008-143205", "primary_object_url": { "basename": "Lindsey_cp_1987.pdf", "content": "final", "filesize": 9992942, "license": "other", "mime_type": "application/pdf", "url": "/856/1/Lindsey_cp_1987.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "High Power Phased Array and Tailored Gain Semiconductor Lasers", "author": [ { "family_name": "Lindsey", "given_name": "Christopher Paul", "clpid": "Lindsey-Christopher-Paul" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "thesis_committee": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Johnson", "given_name": "William Lewis", "clpid": "Johnson-W-L" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Cohen", "given_name": "Donald S.", "clpid": "Cohen-D-S" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Most phase locked semiconductor laser arrays suffer from undesirable twin lobed farfield patterns, making them unsuitable for many applications. In this thesis we make a detailed theoretical and experimental study of this problem, and solve it by tailoring the spatial gain profile across the array. We demonstrate a tailored gain chirped array which emits 450mW into a single beam 3\u00bd\u00b0 wide.
\r\n\r\nStripe geometry lasers for use in phased arrays are examined in Chapter 2, as are design considerations for evanescently coupled phased arrays. A powerful numerical method for analyzing a nearly arbitrary one-dimensional dielectric waveguide with gain and/or loss is described.
\r\n\r\nChapter 3 analyzes in detail the simplest array of two adjacent waveguides, both real index and gain guided and both weakly and strongly coupled. Chapter 4 discusses why a uniform array has a twin lobed farfield pattern, and introduces the concept of a nonuniform real index guided chirped array of lasers with widths which increase monotonically across the array. Real index guided chirped arrays can, in principle, be made to lase with a single lobed farfield pattern. Since such arrays are difficult to fabricate, and will be at least partially gain guided, we concentrate on gain guided structures. The combination of gain tailoring and a high interchannel gain in a proton implanted chirped array enables us to achieve our goal of fabricating a high power array with the single lobed farfield pattern described above.
\r\n\r\nSuch arrays are actually tailored gain broad area lasers. Chapter 5 demonstrates another method for gain tailoring, the \"halftone\" process, which can create nearly arbitrary two-dimensional spatial gain profiles in an optoelectronic device, thereby offering a new degree of freedom to the designer of semiconductor lasers. Single lobed nearly diffraction limited beams from tailored gain broad area lasers 50\u00b5m wide are obtained.
\r\n\r\nAsymmetric tailored gain waveguides have several unusual properties. The technique of Path Analysis for analyzing these complex waveguides is introduced. Fundamental Fourier Transform relationships relating device structure to farfield patterns yield additional insights. Finally, we close with a measurement of the antiguiding parameter and briefly examine some design criteria for practical tailored gain broad area lasers.
\r\n", "doi": "10.7907/9mh8-wv40", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:828", "collection": "thesis", "collection_id": "828", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03012008-134552", "primary_object_url": { "basename": "Lau_byb_1987.pdf", "content": "final", "filesize": 4530865, "license": "other", "mime_type": "application/pdf", "url": "/828/1/Lau_byb_1987.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Small-Signal Frequency Response Theory for Ideal Dc-to-Dc Converter Systems", "author": [ { "family_name": "Lau", "given_name": "Billy Ying Bui", "clpid": "Lau-Billy-Ying-Bui" } ], "thesis_advisor": [ { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" } ], "thesis_committee": [ { "family_name": "Middlebrook", "given_name": "Robert David", "clpid": "Middlebrook-R-D" }, { "family_name": "Caughey", "given_name": "Thomas Kirk", "clpid": "Caughey-T-K" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "clpid": "Vaidyanathan-P-P" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The frequency response problem of switching dc-to-dc converter systems is the problem of computing the small-signal frequency response of the system with respect to its inputs. It arises in the study of the small-signal behavior and in the design of a feedback controller for the dc-to-dc converter system. There are two approaches in tackling the problem: the numerical approach and the analytical approach. This thesis is limited to the analytical approach. There are previous efforts in developing approximate analytical methods for solving the problem; however, these methods are unsatisfactory in one way or another because they are applicable only to few special cases, and valid only in limited range of frequency \u2014 less than half the switching frequency in many cases.
\r\n\r\nThe Small-Signal Frequency Response Theory presented in this thesis is developed to overcome the problems encountered in the application of the approximate analytical methods. Instead of finding an approximate model for a dc-to-dc converter system and postulating that the response of the model is the same as that of the converter system, as in the approximate analytical methods, the new theory computes the frequency response of the perturbed output with respect to perturbations at the control-inputs by the direct application of Fourier Analysis. Hence, the theory is exact in the small-signal limit. Unlike the approximate analytical methods, the results given by the theory are valid at all frequencies provided that the system model used in the calculation of frequency response is valid at all frequencies. In short, the Small-Signal Frequency Response Theory is a mathematical theory for the linearization of an ideal dc-to-dc converter system in the vicinity of its periodic steady state solution.
\r\n\r\nIn the derivation of the results of the Small-Signal Frequency Response Theory, two steps are taken: First, find a difference equation that describes the small-signal motion of the system in the vicinity of the given steady state solution. Second, find the equivalent hold that relates the samples of the perturbed state of the system, given by the difference equation, to the analog output signal. The z-transform of the difference equation with z = esT. is used to relate the spectrum of the sampled perturbed control-input to the spectrum of the sampled perturbed output. The frequency response of the converter system given by the theory resembles the frequency response of a classical single-rate sampled-data system.
\r\n\r\nThe prediction given by the theory and the experimental results for three converter circuits are compared. These three converter circuit have the same basic circuit topology, but different control strategies. The control strategies in these three examples are: constant-switching-frequency PWM, constant-switching-frequency programmed, and bang-bang controlled. It is found that the theory consistently gives good predictions, even up to many times of the switching frequency, while, in many cases, the approximate analytical methods break down.
\r\n\r\nThe theory has the best of both the time domain approach and the frequency domain approach for the analysis of switching dc-to-dc converter systems. It has the exactness of the time domain approach, which uses a difference equation to describe the system, and the measurability of the of frequency domain approach. The exactness and the uniformity of the theory, which has not been achieved before, results in significant impact in the fields of computer-aided design and modelling and analysis in power electronics.
", "doi": "10.7907/mqpe-vz16", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:827", "collection": "thesis", "collection_id": "827", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03012008-134009", "primary_object_url": { "basename": "Kasilingam_dp_1987.pdf", "content": "final", "filesize": 4261116, "license": "other", "mime_type": "application/pdf", "url": "/827/1/Kasilingam_dp_1987.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Topics in Millimeter-Wave Imaging Arrays", "author": [ { "family_name": "Kasilingam", "given_name": "Dayalan P.", "clpid": "Kasilingam-Dayalan-P" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Abu-Mostafa", "given_name": "Yaser S.", "clpid": "Abu-Mostafa-Y-S" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "In this thesis two different types of antenna arrays are investigated as possible configurations for two-dimensional diffraction limited imaging arrays. The first configuration is the \"fly's-eye\" array of microlenses. It is shown that this configuration may be utilized to achieve diffraction limited imaging with theoretical coupling efficiencies of around 50%. The other configuration is the two-dimensional horn array. It is shown that in this configuration, wide-angled horns etched into silicon achieve theoretical coupling efficiencies of 60%. A design for a two-dimensional imaging array, using horn elements of aperture size 1.5\u03bb0 was suggested. Also covered in this thesis are the radiation losses and the substrate-mode losses of coplanar transmission lines. It is shown that at millimeter-wave frequencies these losses are prohibitively high. Finally in the appendix a simulation of Schottky diode mixers is described as a possible design tool for analyzing millimeter-wave detector circuits.
", "doi": "10.7907/rt21-jt48", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:851", "collection": "thesis", "collection_id": "851", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03032008-105407", "primary_object_url": { "basename": "Lam_ww_1987.pdf", "content": "final", "filesize": 6134846, "license": "other", "mime_type": "application/pdf", "url": "/851/1/Lam_ww_1987.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Millimeter-Wave Monolithic Schottky Diode-Grid Phase Shifter", "author": [ { "family_name": "Lam", "given_name": "Wayne W.", "clpid": "Lam-Wayne-W" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Vahala", "given_name": "Kerry J.", "orcid": "0000-0003-1783-1380", "clpid": "Vahala-K-J" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Luhmann", "given_name": "Neville C., Jr.", "clpid": "Luhmann-Neville-C-Jr" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Many applications at millimeter wavelengths require fast electronic phase shifters. In this study, the design of diode-grid phase shifters is presented, the fabrication of diode-grids on monolithic gallium-arsenide substrates is demonstrated, and the measurement of these grids is discussed. A new computer-aided design tool is developed to provide an interactive environment for design and to form a basis for comparing theory and experimental results. Diode-grids have been fabricated on 2 cm by 3 cm gallium-arsenide wafers with 2000 aluminum Schottky diodes. A novel small aperture reflectometer is computerized to use a wave-front division interference technique to measure the reflection coefficient of the grids. A 70\u00b0 phase shift with a 6.5-dB loss was measured at 93 GHz when the bias on the diode-grid was changed from -3V to +1V.
\r\n", "doi": "10.7907/CGD0-XA98", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:928", "collection": "thesis", "collection_id": "928", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03112008-080918", "type": "thesis", "title": "Coupled-Inductor Magnetics in Power Electronics", "author": [ { "family_name": "Zhang", "given_name": "Zhe", "clpid": "Zhang-Zhe" } ], "thesis_advisor": [ { "family_name": "Cuk", "given_name": "Slobodan", "clpid": "Cuk-S" } ], "thesis_committee": [ { "family_name": "Cuk", "given_name": "Slobodan", "clpid": "Cuk-S" }, { "family_name": "Knowles", "given_name": "James K.", "clpid": "Knowles-J-K" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Leakages are inseparably associated with magnetic circuits and are always thought of in three different negative ways: either you have them and you don't want them (transformers), or you don't have them but want them (to limit transformer short circuit currents), or you have them and want them, but you don't have them in the right amount (coupled-inductor magnetic structures). The methods of how to introduce the leakages at appropriate places and in just the right amounts in coupled-inductor magnetic structures are presented here, in order to optimize the performance of switching dc-to-dc converters.
", "doi": "10.7907/7T0E-2219", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:808", "collection": "thesis", "collection_id": "808", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-02282008-090141", "primary_object_url": { "basename": "Bassiri_s_1987.pdf", "content": "final", "filesize": 1767433, "license": "other", "mime_type": "application/pdf", "url": "/808/1/Bassiri_s_1987.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Electromagnetic Wave Propagation and Radiation in Chiral Media", "author": [ { "family_name": "Bassiri", "given_name": "Sassan", "clpid": "Bassiri-Sassan" } ], "thesis_advisor": [ { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" } ], "thesis_committee": [ { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Elachi", "given_name": "Charles", "clpid": "Elachi-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Propagation and radiation of electromagnetic waves in a lossless, reciprocal, chiral medium is studied in this thesis. Such a medium is described electromagnetically by the constitutive relations D = \u03b5E + i\u03b3B and H = i\u03b3E + (1/\u00b5)B. The constants \u03b5, \u00b5, \u03b3 are real and have values that are fixed by the size, shape, and the spatial distribution of the elements that collectively compose the medium. The plane wave propagation in an unbounded chiral medium is considered. The propagation constants are obtained and the polarization properties of electromagnetic waves in such a medium are discussed in detail. The problem of reflection from, and transmission through a semi-infinite chiral medium is solved by obtaining the Fresnel equations. The conditions for the total internal reflection of the incident wave from the interface, and the existance of the Brewster angle are obtained. The effects of the chirality on the polarization and intensity of the reflected wave from the chiral half-space are discussed and illustrated by employing the Stokes parameters. The propagation of electromagnetic waves through an infinite slab of chiral medium is formulated for oblique incidence and solved analytically for the case of normal incidence. The radiation emitted by an oscillating dipole in an unbounded, lossless, chiral medium is calculated. From the constitutive relations and from the time-harmonic Maxwell equations \u2207 x E = i\u03c9B and \u2207 x H = J - i\u03c9D, it is seen that the wave equation for such a medium is given by \u2207 x \u2207 x E - \u03c92\u00b5\u03b5E - 2\u03c9\u00b5\u03b3\u2207 x E = i\u03c9\u00b5J where the source term J is the current density of the oscillating dipole and where E is the electric vector of the radiated field. The desired solution of this wave equation is found by the dyadic Green's function method, that is, by first constructing the dyadic Green's function \u0393 and then evaluating the expression E = i\u03c9\u00b5\u222b\u0393(r,r')\u2022J(r')dV'. The dyadic Green's function \u0393 and the components of the radiated electric field E are obtained in closed form. The components of the radiated B, D, and H fields can be derived from knowledge of E by using the Maxwell equation B = (1/i\u03c9)\u2207 x E and the constitutive relations. The wave impedance of the medium and the radiation resistance of the dipole are also obtained. The effects of the chiral medium on the polarization and intensity of the dipole radiation are discussed.
", "doi": "10.7907/RFST-5K65", "publication_date": "1987", "thesis_type": "phd", "thesis_year": "1987" }, { "id": "thesis:1010", "collection": "thesis", "collection_id": "1010", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03192008-084301", "primary_object_url": { "basename": "Bruno_wm_1986.pdf", "content": "final", "filesize": 6311964, "license": "other", "mime_type": "application/pdf", "url": "/1010/1/Bruno_wm_1986.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Powder Core Dielectric Waveguides", "author": [ { "family_name": "Bruno", "given_name": "William Michael", "clpid": "Bruno-William-Michael" } ], "thesis_advisor": [ { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "thesis_committee": [ { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Pickett", "given_name": "Herbert M.", "clpid": "Pickett-H-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Flexible dielectric waveguides have been demonstrated at 10 GHz and 94 GHz by filling hollow, low dielectric constant polymer tubes with low-loss, high-dielectric constant powders. Flexible guides with losses as low as 0.12 dB/cm were demonstrated at 94 GHz. These guides also exhibited negligible bending loss for radii of curvature greater than 4 cm.
\r\n\r\nThe theory of 3-region cylindrical dielectric waveguide was used to design the powder-filled tube guides, and measured wavelengths for the HE11 mode are in agreement with theoretical values. Sets of dispersion curves were calculated numerically from the theory for waveguide parameters typical to our guides.
\r\n\r\nA powder-filled rectangular groove in the surface of a plastic substrate has also been demonstrated as a dielectric waveguide at 94 GHz. Guide wavelengths measured for these channel guides for various combinations of guide dimensions, powders, and substrate materials agree with values predicted by the approximate theory of Marcatili for the Ey11 mode. Measured transmission losses were as low as 0.09 dB/cm.
\r\n\r\nThe 94 GHz loss tangents of the powders were calculated by extending Marcatili's theory to relate channel guide attenuation to material losses. These calculated values of loss tangent increased with powder packing fraction, as predicted by theories of electromagnetic wave propagation in random heterogeneous media. Estimates of the 94 GHz loss tangents of the solid constituent materials were then obtained from these theories using the powder loss tangents.
\r\n\r\nPowder channel ring resonators had Q's as high as 2400 at 94 GHz in an 8 cm diameter ring. Directional coupling from adjacent straight channel guides was used to form a transmission filter. Marcatili's approximate theory of bending loss for channel guide appears to be inadequate for predicting the curvature losses of these resonators.
\r\n\r\nIn a 10 GHz experiment, the coupling between two parallel powder channel waveguides was measured as a function of their separation. The measured coupling was at variance with that predicted by Marcatili's approximate analysis for parallel channel waveguides.
", "doi": "10.7907/mxe4-ep43", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:1020", "collection": "thesis", "collection_id": "1020", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03192008-121641", "primary_object_url": { "basename": "Haney_mw_1986.pdf", "content": "final", "filesize": 15585280, "license": "other", "mime_type": "application/pdf", "url": "/1020/1/Haney_mw_1986.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Acousto-Optical Time-and-Space Integrating Processors for Real-Time Synthetic Aperture Radar Imaging", "author": [ { "family_name": "Haney", "given_name": "Michael William", "orcid": "0009-0001-8071-5561", "clpid": "Haney-Michael-William" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Elachi", "given_name": "Charles", "orcid": "009-0002-2156-967X", "clpid": "Elachi-C" }, { "family_name": "Masson", "given_name": "Colin R.", "clpid": "Masson-Colin-R" }, { "family_name": "Posner", "given_name": "Edward C.", "clpid": "Posner-E-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Vaidyanathan", "given_name": "P. P.", "orcid": "0000-0003-3003-7042", "clpid": "Vaidyanathan-P-P" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Acousto-optical processors for Synthetic Aperture Radar (SAR) imaging are presented. The new processors produce images at real-time rates by combining the operations of data collection, storage, and processing into a compact time-and-space integrating (TSI) architecture. In the TSI approach the 2-D SAR imaging problem is decomposed into a cascade of 2 distinct operations: a 1-D spatial integration of light for range compression, and a 1-D temporal integration of light for azimuth compression. These two operations are coupled via a common path interferometric scheme that is insensitive to mechanical vibrations.
\r\n\r\nThe results of an experimental characterization of the TSI approach, with simulated point scatterer radar echoes, are reported. The performance issues of interferometric bias removal, dynamic range, and resolution are addressed. The architecture is generalized to correct for range migration and the results of a range walk compensation experiment are presented. A programmable version of the TSI architecture, in which the fixed azimuth reference mask is replaced by an acousto-optic light modulator, is described. The application of the programmable architecture to both strip-map and spot-light mode SAR is analyzed and experimentally verified.
", "doi": "10.7907/64T4-7N83", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:11461", "collection": "thesis", "collection_id": "11461", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:04152019-101001395", "type": "thesis", "title": "Optical Interactions in a Dielectric Material with Multiple Perturbations", "author": [ { "family_name": "Lee", "given_name": "Hyuk", "clpid": "Lee-Hyuk" } ], "thesis_advisor": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "thesis_committee": [ { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The interaction of light propagating through a dielectric material with multiple perturbations is investigated.
\r\n\r\nA general coupled mode theory of two gratings is presented. The acousto-electro-optic effect is introduced as an example of an indirect interaction due to the acousto-optic and electro-optic effects. The acousto-electro-optic effect is analyzed using the general theory and is demonstrated experimentally. The application of this effect to light modulation and deflection is discussed in detail. Also a correlator that is based on the photorefractive acousto-electrooptic effect is demonstrated and analyzed theoretically.
", "doi": "10.7907/ek2w-4557", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:3700", "collection": "thesis", "collection_id": "3700", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09222006-170253", "type": "thesis", "title": "Sliding Mode Control of Power Converters", "author": [ { "family_name": "Venkataramanan", "given_name": "Ramanarayanan", "clpid": "Venkataramanan-Ramanarayanan" } ], "thesis_advisor": [ { "family_name": "Cuk", "given_name": "Slobodan", "clpid": "Cuk-S" } ], "thesis_committee": [ { "family_name": "Cuk", "given_name": "Slobodan", "clpid": "Cuk-S" }, { "family_name": "Caughey", "given_name": "Thomas Kirk", "clpid": "Caughey-T-K" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Thompson", "given_name": "Peter M.", "clpid": "Thompson-Peter-M" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Switched mode power converters are being used extensively for the purpose of efficient power conversion. Such converters are nonlinear, time variant systems. In the past such converters were being modelled using the state space averaging method. The theory of variable structure systems (VSS), and sliding mode control form a mutually complementary analysis and design tools for the control of switched mode power converters. The application of sliding mode control is presented for dc-to-dc converters and electrical motor drives in this thesis. The concept of sliding mode control is brought out through exhaustive examples of second order systems. The equivalent control, an analysis method of VSS, is applied to obtain transfer function description of dc-to-dc power converters. The sliding mode control is applied to the control problem of dc-to-dc power converters and speed controlled electrical drives to develop practical design techniques. The practical design methods are confirmed through experimental results.
", "doi": "10.7907/230A-P786", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:901", "collection": "thesis", "collection_id": "901", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03082008-083912", "primary_object_url": { "basename": "Smith_js_1986.pdf", "content": "final", "filesize": 9510713, "license": "other", "mime_type": "application/pdf", "url": "/901/1/Smith_js_1986.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "III-V Molecular Beam Epitaxy Structures for Electronic and Optoelectronic Applications", "author": [ { "family_name": "Smith", "given_name": "John Stephen", "clpid": "Smith-John-Stephen" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "thesis_committee": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Corngold", "given_name": "Noel Robert", "clpid": "Corngold-N-R" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Mead", "given_name": "Carver", "orcid": "0000-0003-4051-0462", "clpid": "Mead-C-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Molecular beam epitaxy (MBE), a method for depositing epitaxial semiconductor layers with an extreme degree of control, has previously been limited largely to featureless substrates. This thesis describes a procedure for high quality MBE growth over finely patterned GaAs substrates, which is suitable for device fabrication requiring lateral definition of small (~ 1-2 micron) dimension. The results of series of experiments determining the characteristics of MBE growth over patterned substrates are presented. Temperature and flux ratio dependence of faceting during MBE growth over patterned substrates is shown for temperatures ranging from 580\u00b0 C to 700\u00b0 C and for As/Ga flux ratios from 1.4:1 to 4:1, and surface diffusion lengths for gallium are measured. The (811) and (411) facets are shown to have growth rates which are at a local maximum and minimum, respectively, for facets tilted in the [01̅1] direction, and implications with respect to other experiments on the atomic growth kinetics on (100) facets are discussed. The material grown over facets tilted in the [0111 direction is shown to be of high quality, with electroluminescence equal to that over the (100) plane.
\r\n\r\nThis method was used for the fabrication of an index guided laser structure, with an optical guide similar to that of the liquid phase grown channeled substrate planer laser structure, as well as tightly packed arrays of these lasers. Yields of individual lasers exceeded 90 percent, and thresholds were uniform to 10 percent. Other potential applications for this technique include a vertical structure high electron mobility transistor, formation of \"quantum wire\" structures, and methods of directly contacting quantum well layers for device applications and research purposes.
\r\n\r\nCertain aspects of transport of hot electrons over quantum wells are discussed, with application to several types of devices, including a new type of infrared detector structure, a solid state electron multipler, and a proposed quantum well base transistor.
", "doi": "10.7907/r489-8025", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:927", "collection": "thesis", "collection_id": "927", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03112008-080410", "primary_object_url": { "basename": "Zah_c_1986.pdf", "content": "final", "filesize": 7156226, "license": "other", "mime_type": "application/pdf", "url": "/927/1/Zah_c_1986.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Millimeter-Wave Monolithic Schottky Diode Imaging Arrays", "author": [ { "family_name": "Zah", "given_name": "Chung-en", "clpid": "Zah-Chung-en" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Pine", "given_name": "Jerome", "clpid": "Pine-J" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Luhmann", "given_name": "Neville C., Jr.", "clpid": "Luhmann-Neville-C-Jr" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Inexpensive and compact imaging systems with high sensitivity are needed for millimeter waves. In this study, the calculated efficiencies of elementary integrated-circuit feed antennas show that the antennas with substrate lenses are potentially better feeds than those without substrate lenses. Planar Schottky diodes are integrated with bow-tie antennas to form a one dimensional array. The energy is focused onto the antenna through a silicon lens placed on the back of the gallium-arsenide substrate. Putting a polystyrene cap on the silicon lens has been demonstrated to be an effective way to reduce the reflection loss. A self-aligning process together with proton isolation has been developed to make the planar Schottky diodes with a 1.1-THz zero-bias cutoff frequency. The antenna coupling efficiency and imaging properties of the system are studied by video detection measurements at 94 GHz. As a heterodyne receiver, a double-sideband mixer conversion loss of 11.2 dB and noise temperature of 3770\u00b0K have been achieved at a local oscillator frequency of 91 GHz.
\r\n", "doi": "10.7907/YSN2-8F19", "publication_date": "1986", "thesis_type": "phd", "thesis_year": "1986" }, { "id": "thesis:3155", "collection": "thesis", "collection_id": "3155", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08172005-102232", "primary_object_url": { "basename": "Tong_pp_1985.pdf", "content": "final", "filesize": 5850564, "license": "other", "mime_type": "application/pdf", "url": "/3155/1/Tong_pp_1985.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Millimeter-Wave Integrated-Circuit Antenna Arrays", "author": [ { "family_name": "Tong", "given_name": "Peter Ping Tak", "clpid": "Tong-Peter-Ping-Tak" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Knowles", "given_name": "James K.", "clpid": "Knowles-J-K" }, { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" }, { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents three different types of millimeter-wave integrated-circuit antenna array. They are a linearly polarized antenna array that can form polarization and intensity line images, a circularly polarized spiral antenna and a two-dimensional tracking antenna array. They are all integrated-circuit antennas with detectors on quartz substrates using quasi-optical systems to collect and focus the waves.
\r\n", "doi": "10.7907/ddxq-rj80", "publication_date": "1985", "thesis_type": "phd", "thesis_year": "1985" }, { "id": "thesis:8553", "collection": "thesis", "collection_id": "8553", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:07172014-130847340", "type": "thesis", "title": "Investigation of Bulk Indium Antimonide as Heterodyne Detector for the Submillimeter Wavelength Region", "author": [ { "family_name": "Brown", "given_name": "Elliott R.", "clpid": "Brown-Elliott-R" } ], "thesis_advisor": [ { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" } ], "thesis_committee": [ { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" }, { "family_name": "Johnson", "given_name": "William Lewis", "clpid": "Johnson-W-L" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Bulk n-InSb is investigated at a heterodyne detector for the submillimeter wavelength region. Two modes of operation are investigated: (1) the Rollin or hot electron bolometer mode (zero magnetic field), and (2) the Putley mode (quantizing magnetic field). The highlight of the thesis work is the pioneering demonstration or the Putley mode mixer at several frequencies. For example, a double-sideband system noise temperature of about 510K was obtained using a 812 GHz methanol laser for the local oscillator. This performance is at least a factor or 10 more sensitive than any other performance reported to date at the same frequency. In addition, the Putley mode mixer achieved system noise temperatures of 250K at 492 GHz and 350K at 625 GHz. The 492 GHz performance is about 50% better and the 625 GHz is about 100% better than previous best performances established by the Rollin-mode mixer. To achieve these results, it was necessary to design a totally new ultra-low noise, room-temperature preamp to handle the higher source impedance imposed by the Putley mode operation. This preamp has considerably less input capacitance than comparably noisy, ambient designs.
\r\n\r\nIn addition to advancing receiver technology, this thesis also presents several novel results regarding the physics of n-InSb at low temperatures. A Fourier transform spectrometer was constructed and used to measure the submillimeter wave absorption coefficient of relatively pure material at liquid helium temperatures and in zero magnetic field. Below 4.2K, the absorption coefficient was found to decrease with frequency much faster than predicted by Drudian theory. Much better agreement with experiment was obtained using a quantum theory based on inverse-Bremmstrahlung in a solid. Also the noise of the Rollin-mode detector at 4.2K was accurately measured and compared with theory. The power spectrum is found to be well fit by a recent theory of non-equilibrium noise due to Mather. Surprisingly, when biased for optimum detector performance, high purity InSb cooled to liquid helium temperatures generates less noise than that predicted by simple non-equilibrium Johnson noise theory alone. This explains in part the excellent performance of the Rollin-mode detector in the millimeter wavelength region.
\r\n\r\nAgain using the Fourier transform spectrometer, spectra are obtained of the responsivity and direct detection NEP as a function of magnetic field in the range 20-110 cm-1. The results show a discernable peak in the detector response at the conduction electron cyclotron resonance frequency for magnetic fields as low as 3 KG at bath temperatures of 2.0K. The spectra also display the well-known peak due to the cyclotron resonance of electrons bound to impurity states. The magnitude of responsivity at both peaks is roughly constant with magnet1c field and is comparable to the low frequency Rollin-mode response. The NEP at the peaks is found to be much better than previous values at the same frequency and comparable to the best long wavelength results previously reported. For example, a value NEP = 4.5 x 10-13W/Hz1/2 is measured at 4.2K, 6 KG and 40 cm-1. Study of the responsivity under conditions of impact ionization showed a dramatic disappearance of the impurity electron resonance while the conduction electron resonance remained constant. This observation offers the first concrete evidence that the mobility of an electron in the N = 0 and N = 1 Landau levels is different. Finally, these direct detection experiments indicate that the excellent heterodyne performance achieved at 812 GHz should be attainable up to frequencies of at least 1200 GHz.
", "doi": "10.7907/wm40-4k69", "publication_date": "1985", "thesis_type": "phd", "thesis_year": "1985" }, { "id": "thesis:1101", "collection": "thesis", "collection_id": "1101", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-03242008-112135", "primary_object_url": { "basename": "Whitney_te_1985.pdf", "content": "final", "filesize": 9115712, "license": "other", "mime_type": "application/pdf", "url": "/1101/1/Whitney_te_1985.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Hierarchical Composition of VLSI Circuits", "author": [ { "family_name": "Whitney", "given_name": "Telle Elizabeth", "orcid": "0000-0002-4580-2395", "clpid": "Whitney-Telle-Elizabeth" } ], "thesis_advisor": [ { "family_name": "Mead", "given_name": "Carver", "orcid": "0000-0003-4051-0462", "clpid": "Mead-C-A" } ], "thesis_committee": [ { "family_name": "Mead", "given_name": "Carver", "orcid": "0000-0003-4051-0462", "clpid": "Mead-C-A" }, { "family_name": "Seitz", "given_name": "Charles L.", "clpid": "Seitz-C-L" }, { "family_name": "Barr", "given_name": "Alan H.", "clpid": "Barr-A-H" }, { "family_name": "Lyon", "given_name": "Richard F.", "clpid": "Lyon-Richard-F" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "A transistor level representation for VLSI circuits is presented. This representation is simple but general, technology independent, hierarchical, and maintains connectivity, circuit schematic information, and the information for mask geometry.
\r\n\r\nA transistor level cell is represented as the interconnection of devices along with their types, sizes and placement, and the cell's typed ports. Connection is represented explicitly by shared connection points. The ports describe the interface between this cell and other cells. This representation, together with a set of synthesis and analysis rules, enforces the description of strictly legal designs. The synthesis rules ensure that each structure is correct by construction. The analysis rules check for geometrical design rule violations which cannot, by their nature, be enforced by construction.
\r\n\r\nA file of technology dependent information indicates how to implement each transistor type, interconnect type and connection point type, as well as how structure types may interact.
\r\n\r\nCells described in this representation may be composed hierarchically to form larger cells. Given a valid composition, the topology, geometry and connectivity of the composite structure is guaranteed to be legal.
\r\n\r\nA working system supporting this hierarchical representation is also described. This system currently supports design rules for nMOS and cMOS/bulk, and has produced chip descriptions that have been both fabricated and tested.
", "doi": "10.7907/ykeb-r680", "publication_date": "1985", "thesis_type": "phd", "thesis_year": "1985" }, { "id": "thesis:84", "collection": "thesis", "collection_id": "84", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01092007-104136", "primary_object_url": { "basename": "Neikirk_dp_1984.pdf", "content": "final", "filesize": 14712401, "license": "other", "mime_type": "application/pdf", "url": "/84/1/Neikirk_dp_1984.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Integrated Detector Arrays for High Resolution Far-Infrared Imaging", "author": [ { "family_name": "Neikirk", "given_name": "Dean Paul", "clpid": "Neikirk-Dean-Paul" } ], "thesis_advisor": [ { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "thesis_committee": [ { "family_name": "Pine", "given_name": "Jerome", "clpid": "Pine-J" }, { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Imaging systems designed to operate in the millimeter and submillimeter portion of the spectrum (often referred to as the far-infrared) require the development of focal plane detector arrays to simplify their construction. In this study the general characteristics of an antenna array intended to provide diffraction limited imaging are discussed. Two line-imaging bow-tie antenna arrays utilizing the hyperhemispherical substrate lens optical system and operating at 1.22mm and 119\u00b5m, are demonstrated. Two new far-infrared detectors, the bismuth air-bridge microbolometer and the bismuth-antimony microthermocouple, have been used with these arrays. Thermal models and performance data for these detectors are given. Finally, the photolithographic processes used to fabricate the detectors and antennas are discussed.
\r\n", "doi": "10.7907/jxk1-9t91", "publication_date": "1984", "thesis_type": "phd", "thesis_year": "1984" }, { "id": "thesis:4", "collection": "thesis", "collection_id": "4", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01022007-112439", "primary_object_url": { "basename": "Polivka_wm_1984.pdf", "content": "final", "filesize": 15509733, "license": "other", "mime_type": "application/pdf", "url": "/4/1/Polivka_wm_1984.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Applications of Magnetics to Problems in Switched-Mode Power Conversion", "author": [ { "family_name": "Polivka", "given_name": "William M.", "clpid": "Polivka-William-M" } ], "thesis_advisor": [ { "family_name": "Cuk", "given_name": "Slobodan", "clpid": "Cuk-S" } ], "thesis_committee": [ { "family_name": "Barnes", "given_name": "Charles A.", "clpid": "Barnes-C-A" }, { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Cuk", "given_name": "Slobodan", "clpid": "Cuk-S" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Two topics are presented which advance the use of magnetic devices in switched-mode power converters. Part I discusses a novel method of detecting impending saturation of magnetic materials. The technique exploits the interaction of perpendicular magnetic fields to provide a simple, direct and continuous measure of the increasing nonlinearity of the material without any elaborate unconventional devices or complex electronic circuitry. Theoretical foundations and applications to ferrite cores in switching converters are given. Specific practical hardware examples are described including magnetics for a 4-kilowatt push-pull buck converter. Part II presents a discussion of the analysis of zero ripple integrated magnetic structures. These complex devices are of great interest in the field of switched mode power conversion because they have the ability to exclude ac currents from some of their windings when they are excited by ac voltages. A thorough analysis is carried out to establish which of the many characteristic parameters of these devices are responsible for the unusual zero ripple behavior. Practical methods of modelling and analysis are developed by which a designer can quickly determine the conditions required for zero ripple. Equivalent electric circuit models are given to aid in the electrical design of converters and to support the simple physical explanations of the observed phenomena including the effects of parasitic quantities. A number of experiments confirm the validity of the models.
", "doi": "10.7907/31G4-8128", "publication_date": "1984", "thesis_type": "phd", "thesis_year": "1984" }, { "id": "thesis:297", "collection": "thesis", "collection_id": "297", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01232007-143259", "primary_object_url": { "basename": "Warne_l_1984.pdf", "content": "final", "filesize": 3394777, "license": "other", "mime_type": "application/pdf", "url": "/297/1/Warne_l_1984.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Electromagnetic Radiation and Scattering in a Plasma with an Azimuthal Biasing Field", "author": [ { "family_name": "Warne", "given_name": "Larry Kevin", "clpid": "Warne-Larry-Kevin" } ], "thesis_advisor": [ { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" } ], "thesis_committee": [ { "family_name": "Martel", "given_name": "Hardy Cross", "clpid": "Martel-H-C" }, { "family_name": "Psaltis", "given_name": "Demetri", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Kath", "given_name": "William L.", "clpid": "Kath-William-L" }, { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The problem of radiation from an electric line source in a homogeneous, cold, incompressible electron plasma is considered when a large static current is superposed. The static axial current gives rise to a magnetostatic biasing field which is oriented in the azimuthal direction and varies with radial distance. When the driving frequency is greater than the plasma frequency, and the medium is assumed to be unbounded, the presence of the static current reduces the amount of radiation. On the other hand, if the driving frequency is less than the plasma frequency and the medium is assumed to be bounded, the amount of radiation is increased.
\r\n\r\nThe problem of scattering from an axial current in a plasma is also considered. The medium in this problem is taken to be a bounded column of plasma containing a radially distributed axial current. At normal incidence the scattered wave contains a cross polarized field component due to the gyrotropic nature of the column. The scattered cross polarized component vanishes in the incident direction as well as in the backward direction. This null is explained by considering the effect of Faraday rotation on various rays traversing the column. Solutions to the scattering problem when the axial current density varies inversely with radial distance are considered in some detail. This case is labeled \"homogeneous\" since the dielectric tensor does not vary with radial distance and the resulting field equations are thus simplified. The field behavior in the vicinity of the origin is also considered in detail since phenomena similar to those encountered in wedge type media (unbounded fields) occur.
", "doi": "10.7907/tja8-zp12", "publication_date": "1984", "thesis_type": "phd", "thesis_year": "1984" }, { "id": "thesis:11287", "collection": "thesis", "collection_id": "11287", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:11282018-101712728", "primary_object_url": { "basename": "Margoliash_D_1984.pdf", "content": "final", "filesize": 41114274, "license": "other", "mime_type": "application/pdf", "url": "/11287/1/Margoliash_D_1984.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Songbirds, Grandmothers, Templates: a Neuroethological Approach", "author": [ { "family_name": "Margoliash", "given_name": "Daniel", "orcid": "0000-0003-0002-3117", "clpid": "Margoliash-Daniel" } ], "thesis_advisor": [ { "family_name": "Fender", "given_name": "Derek H.", "clpid": "Fender-D-H" } ], "thesis_committee": [ { "family_name": "Ary", "given_name": "James P.", "clpid": "Ary-James-P" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Konishi", "given_name": "Masakazu", "clpid": "Konishi-M" }, { "family_name": "Van Essen", "given_name": "David C.", "orcid": "0000-0001-7044-4721", "clpid": "Van-Essen-D-C" }, { "family_name": "Fender", "given_name": "Derek H.", "clpid": "Fender-D-H" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Songbirds such as the white-crowned sparrow memorize the song of conspecific adults during a critical period early in life, and later in life develop song by utilizing auditory feedback. Neurons in one of the telencephalic nuclei controlling song have recently been shown to respond to acoustic stimuli. I investigated the auditory response properties of units in this nucleus using a technique that permitted great flexibility in manipulating complex stimuli such as song. A few of the units exhibited considerable selectivity for the individual's own song. In wild-caught birds, song specific units exhibited intra-dialect selectivity. In those birds that sang abnormal songs due to laboratory manipulation of song exposure during the critical period for song learning, units were selective for the abnormal songs. By systematic modification of a song, and by construction of complex synthetic sounds mimicking song, the acoustic parameters responsible for the response selectivity were identified. Song specific units responded to sequences of two song parts, but not to the parts in isolation. Modification of the frequencies of either part of the sequence, or increasing the interval between the parts, varied the strength of the response. Thus, temporal as well as spectral parameters were important for the response. When sequences of synthetic sounds mimicking song were effective in evoking an excitatory response, the response was sensitive to the aforementioned manipulations. With these techniques it was possible to elucidate the acoustic parameters required to excite song specific units. All songs of the repertoire eliciting a strong excitatory response contained the appropriate parameters, which were missing from all weakly effective, ineffective, or inhibitory songs. These observations suggest that the ontogenetic modification of integrative neural mechanisms underlying song learning or song crystalization is reflected at the level of single neurons.
\r\n", "doi": "10.7907/2yhr-5t19", "publication_date": "1984", "thesis_type": "phd", "thesis_year": "1984" }, { "id": "thesis:4437", "collection": "thesis", "collection_id": "4437", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-11072005-080724", "primary_object_url": { "basename": "Ho_kt_1984.pdf", "content": "final", "filesize": 5171514, "license": "other", "mime_type": "application/pdf", "url": "/4437/1/Ho_kt_1984.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Evolution of Nitrogen Impurities in Metal-Silicon Binary Couples and their Effect on Silicide Formation", "author": [ { "family_name": "Ho", "given_name": "Kuo Ting", "clpid": "Ho-Kuo-Ting" } ], "thesis_advisor": [ { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "thesis_committee": [ { "family_name": "Barnes", "given_name": "Charles A.", "clpid": "Barnes-C-A" }, { "family_name": "Johnson", "given_name": "William Lewis", "clpid": "Johnson-W-L" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Wilts", "given_name": "Charles Harold", "clpid": "Wilts-C-H" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The possible ways in which nitrogen may be present in and interact with metal silicides are outlined. It is shown that, although contaminant nitrogen can be easily eliminated in deposition systems and processing ambients, understanding the role of nitrogen in metals and metal silicides may be important for various nitridation processes used for VLSI fabrication.
\r\n\r\nNitrogen isotope 15N is controllably introduced into either the metal or silicon in a metal-silicon binary couple. Silicide formation is induced by vacuum annealing. After various thermal treatments, 15N is profiled by the 15N(p,\u03b1)12C nuclear reaction. A detailed description of this technique is given.
\r\n\r\nThe metals investigated are Pd, Ni, Co, Pt, Ta, Mo and Ti. Metal silicides are grouped into three categories according to the moving species during silicide formation: metal, silicon or both. The interpretation of nitrogen evolution during silicide formation is based on the identity of the moving species. A wide variety of nitrogen redistribution patterns (segregation, incorporation, accumulation, dilution and fast diffusion) are observed in different samples, depending on parameters such as nitrogen diffusivity and solubility in its host matrix, and nitrogen bond strength to the silicide forming species.
\r\n\r\nThe presence of nitrogen sometimes will slow down the silicide growth rate. The degree of slowing down generally depends on the amount of nitrogen incorporated. In case of refractory metal, a large concentration up to 25 at% of oxygen is found to be incorporated during metal film deposition. The redistribution of oxygen during annealing is investigated using the 16O(d,\u03b1)14N nuclear reaction.
\r\n\r\nTwo additional studies on different subjects are reported. The first one investigates the dry and wet oxidation behavior of Ti and Hf nitrides. A parabolic oxidation rate is found in all cases except the wet oxidation of HfN. The other study extends the work on dopant enhanced epitaxial regrowth of Si to three substrate orientations. It is found that the enhancement factor is the same, independent of the substrate orientation. An improved crystalline quality is observed for epitaxial Si regrown on an <111> substrate.
\r\n", "doi": "10.7907/tz19-ww79", "publication_date": "1984", "thesis_type": "phd", "thesis_year": "1984" }, { "id": "thesis:4391", "collection": "thesis", "collection_id": "4391", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-11032005-130746", "primary_object_url": { "basename": "Bartur_m_1984.pdf", "content": "final", "filesize": 1310808, "license": "other", "mime_type": "application/pdf", "url": "/4391/1/Bartur_m_1984.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Utilization of Silicides for VLSI-Contacts with Aluminum and Thermal Oxidation", "author": [ { "family_name": "Bartur", "given_name": "Meir", "clpid": "Bartur-Meir" } ], "thesis_advisor": [ { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "thesis_committee": [ { "family_name": "Lau", "given_name": "Silvanus S.", "clpid": "Lau-Silvanus-S" }, { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The potential role of silicides in VLSI (very large scale integration) Si technology is described. A survey of trends and requirements exposes two difficult technological issues as the device dimensions shrink: contacts to the individual devices and interconnections between devices or functional blocks on the Si chip. For both, silicides play an important role.
\r\n\r\nThe contact between the Si that contains the device and the top Al layer (Al is the preferred metal for metallization) has to be thermally stable, reproducible, reliable, and have low contact resistivity. After a brief survey of the available diffusion barriers designed to suppress the Al interaction with Si, I concentrate on the sacrificial barrier structure. The generalized layered structure approach, utilizing Si/silicide/sacrificial barrier/Al, is analyzed with Ti, V, or Cr as the sacrificial barrier material. A study of Cr as a barrier between Al and NiSi, Pd2Si, or PtSi reveals that impurities in the as-deposited Cr film determine the barrier properties. The concept of the sacrificial barrier is critically reexamined in the light of these results. A study of a thin W layer, which is probably a stuffed barrier, as a barrier between NiSi and Al is reported. An outlook to future trends and approaches concludes this part of the thesis.
\r\n\r\nA major attribute of silicides as interconnection material is their capability to form SiO2 upon thermal oxidation. A study of the oxidation characteristics of near-noble metal silicides (Co, Ni, Pd, and Pt) is presented in the second part of this thesis. The oxidation kinetics and the mass transport through the silicide during oxidation are explored. The role of mass transport in the oxidation kinetics is reviewed in the light of all the reported experimental results. The effect of oxidation on: a) the epitaxial registration of a silicide on <111> Si substrate (NiSi2, CoSi2, and Pd2Si), and b) the electrical resistivity (NiSi2 and CoSi2), is explored. Properties of SiO2 grown on different (Ti, Co, Ni, Pd and Pt) silicides are found to be the same as for SiO2 grown on Si substrates, except for the lower (~1.5 x 106 V/cm) dielectric breakdown. A preliminary implementation of interconnections with NiSi2 demonstrates the applicabilty of this silicide for VLSI. Finally, a novel interconnection scheme is advanced as a possible method to produce self-confined metal interconnection lines.
\r\n", "doi": "10.7907/V36Y-BW59", "publication_date": "1984", "thesis_type": "phd", "thesis_year": "1984" }, { "id": "thesis:3294", "collection": "thesis", "collection_id": "3294", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-08312006-083650", "type": "thesis", "title": "I. Parametric Study of Optically Pumped Far-Infrared Waveguide Lasers. II. Theory and Experiment of Folded Fabry-Perot Quasi-Optical Ring Resonator Diplexer", "author": [ { "family_name": "Chiou", "given_name": "Arthur Er-Terg", "clpid": "Chiou-Arthur-Er-Terg" } ], "thesis_advisor": [ { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "thesis_committee": [ { "family_name": "Culick", "given_name": "Fred E. C.", "clpid": "Culick-F-E-C" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis consists of two parts, each representing a different aspect of far-infrared (FIR) physics and technology.
\r\n\r\nPart I deals with the problems related to the physics and the design of one of the extremely useful coherent sources in the FIR region of the electromagnetic spectrum: the optically-pumped FIR waveguide laser. The effects of small waveguide diameter were studied here particularly because of their importance to the practical realization of a compact coherent FIR laser. Two known theoretical models were used to analyze the performance of CH3OH 118 \u00b5m laser and CH3F 496 \u00b5m laser; the results from these models were compared with the results of our experimental parametric study on CH3OH 118 \u00b5m laser. A simplified model of Lourtioz and Adde agrees reasonably well, in a semiquantitative sense, with our experimental results. The \u03bb2/a3 dependence of distributed waveguide loss for FIR radiation turns out to be the major factor that limits the waveguide size.
\r\n\r\nPart II deals with a problem related to the physics and design of a diplexer for application in the FIR heterodyne radiometry, where signals from the local oscillator and the received signal have to be directed into a detector for frequency mixing and for further signal processing. Since the signal of interest is typically very weak, the diplexer should serve the dual purpose of directing the two beams and filtering out the unwanted frequency components (noise) to enhance the signal to noise ratio, and do so with minimum loss.
\r\n\r\nThe optimum design parameters for a folded Fabry-Perot quasi-optical ring resonator diplexer were derived, and its performance was investigated both theoretically and experimentally. The results were compared with those of the similar diplexers of non-optimum geometry. The advantages and limitations of the optimum diplexer design are analyzed.
", "doi": "10.7907/eeh1-p029", "publication_date": "1983", "thesis_type": "phd", "thesis_year": "1983" }, { "id": "thesis:3355", "collection": "thesis", "collection_id": "3355", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09062006-083609", "primary_object_url": { "basename": "Harder_cs_1983.pdf", "content": "final", "filesize": 11181635, "license": "other", "mime_type": "application/pdf", "url": "/3355/1/Harder_cs_1983.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Bistability, High Speed Modulation, Noise and Pulsations in GaAlAs Semiconductor Lasers", "author": [ { "family_name": "Harder", "given_name": "Christoph S.", "clpid": "Harder-Christoph-S" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "thesis_committee": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Peck", "given_name": "Charles W.", "clpid": "Peck-C-W" }, { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis describes seven different subjects relevant to semiconductor laser diodes which fall in the following three categories: Bistability and pulsations, high speed modulation and noise.
\r\n\r\nBistable semiconductor lasers based on inhomogeneous current injection, achieved with a split contact scheme, were proposed around 20 years ago. However, actual devices showed no or only a small hysteresis and they were in addition beset by pulsations for reasons not well understood at the time. In this thesis we show that lasers with an optimized design can display bistability with a giant hysteresis. Crucial to the understanding of the bistable laser is a negative differential resistance across the absorber section, reminiscent of a tunnel diode characteristic. Depending on the electrical biasing circuit this negative differential resistance leads to bistability or light-jumps and self-pulsations. A simple model based on the conventional rate equations explains the observed behavior. Investigation of the switching dynamics of this optoelectronic device reveals a delay time which is critically dependent on the trigger pulse amplitude and which is typically in the order of a few nanoseconds at a power-delay product of 100pJ. We also investigate the characteristic of this laser coupled to an external optical cavity and we demonstrate that this bistable laser can be used as a self-coupled stylus for optical disk readout. Under a different biasing condition this laser coupled to an external optical cavity can be used to generate ultrashort optical pulses through passive mode locking. Unlike previous mode locking techniques, the method presented here does not rely on absorption introduced by damaging the crystal and is consequently much more reliable.
\r\n\r\nThe high speed modulation behavior of semiconductor lasers is investigated theoretically and experimentally. In this thesis we derive the fundamental limits of injection lasers for pulse modulation and small signal modulation. We place emphasis on developing laser structures optimized for high frequency modulation and experiments on such structures show that they can be modulated at frequencies up to 8GHz. At these frequencies the parasitic elements can no longer be neglected and they are included in the analysis.
\r\n\r\nThe noise equivalent circuit of a semiconductor laser diode is derived from the rate equations including Langevin noise sources. This equivalent circuit allows a straightforward calculation of the noise and frequency modulation characteristics of a laser diode combined with electronic components. The field spectrum of injection lasers is observed also experimentally. It is a unique feature of injection lasers that their linewidth is increased through a strong amplitude phase coupling by the factor (1 + \u03b12) where \u03b1 is the linewidth enhancement factor. A model is developed which shows that the same factor \u03b1 enters in the small signal modulation characteristics and a careful measurement of the small signal amplitude and phase modulation at high frequencies enables us to obtain this important factor \u03b1 for the first time by a direct measurement.
", "doi": "10.7907/jxwz-e844", "publication_date": "1983", "thesis_type": "phd", "thesis_year": "1983" }, { "id": "thesis:3523", "collection": "thesis", "collection_id": "3523", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09132006-153307", "type": "thesis", "title": "Measurements of Magnetic Field Fluctuations in the Caltech Research Tokamak", "author": [ { "family_name": "Hedemann", "given_name": "Mark Allen", "clpid": "Hedemann-Mark-Allen" } ], "thesis_advisor": [ { "family_name": "Gould", "given_name": "Roy Walter", "clpid": "Gould-R-W" } ], "thesis_committee": [ { "family_name": "Gould", "given_name": "Roy Walter", "clpid": "Gould-R-W" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Saffman", "given_name": "Philip G.", "clpid": "Saffman-P-G" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "An experimental investigation of magnetic field fluctuations in a research tokamak plasma has been performed. The fluctuations were measured with movable probes inserted directly into the plasma. Estimates of the fluctuating field strength, power spectral density, and correlation lengths have been made by calculations on the raw data. The fluctuations were found to be of comparable strength for the radial and poloidal components, while the toroidal component was found to be at least a factor of 5 weaker in strength. The fluctuating field strength showed no apparent dependence on plasma current and safety factor at the edge, but increased with electron density during gas puffing and as the minor radius of measurement was decreased.
\r\n\r\nThe power spectral density indicated that the fluctuations could be divided into two frequency regions. The low frequency region (f < 100 kHz) was dominated by coherent MHD modes with correlation lengths on the order of the tokamak size. The high frequency (f > 100 kHz) region appeared to be turbulent in nature with short correlation lengths in the poloidal direction (< .01 m), but longer correlation lengths in the radial direction (> .04 m). The high frequency region showed a roll-off in frequency of \u03b4Br of approximately f-2.5.
\r\n\r\nThe results are compared with theories of fluctuation sources and the effects of fluctuations on anomalous electron thermal transport. The best fit to the high frequency region spectral density is given by a statistical theory of fluctuations. The fluctuating field strength appears to be more than an order of magnitude too small to account for the anomalous electron thermal transport using stochastic field theory.
", "doi": "10.7907/z70q-f715", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:3519", "collection": "thesis", "collection_id": "3519", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09132006-133617", "type": "thesis", "title": "Long Wavelength GaInAsP/InP Semiconductor Lasers for Optical Communications", "author": [ { "family_name": "Chen", "given_name": "Pei-Chuang", "clpid": "Chen-Pei-Chuang" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "thesis_committee": [ { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Optical fiber communication systems have shifted toward the long wavelength range of 1.2-1.6 \u00b5m due to lower losses and dispersion available with high quality fibers. The quaternary GaInAsP/InP material system has evolved as the most promising system for light sources in this range.
\r\n\r\nIndium phosphide electronic devices are expected to possess high frequency switching capabilities, but present device technology is still rather primitive. In anticipation of future developments, which will render opto-electronic integration in this system advantageous, two laser structures on semi-insulating InP substrates were demonstrated. The substrate permits electrical isolation between components and thus is ideal in planar integration of the lasers with electronic devices.
\r\n\r\nLow threshold lasers can only be achieved when the active region is properly defined in two dimensions to provide good optical and carrier confinement. Present techniques usually require difficult and intricate growth step of two-step liquid phase epitaxy. Embedded epitaxy, by growth through a mask, offers a simple yet elegant means of two dimensional definition of the active region with only a single growth step. Low threshold lasers were fabricated with this technique and demonstrated its potential applications.
\r\n\r\nAll GaInAsP/InP lasers show accelerated increase of threshold current with temperature of a different nature than similar GaA1As lasers. To understand the origin of this phenomenon, calculations were made of the Auger process in these lasers, and have demonstrated that they play a very important role in the temperature behavior of GaInAsP/InP lasers.
\r\n", "doi": "10.7907/51sv-sm58", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:3363", "collection": "thesis", "collection_id": "3363", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09062006-152644", "type": "thesis", "title": "Dielectric Waveguides for Millimeter Waves", "author": [ { "family_name": "Schweig", "given_name": "Edgard", "clpid": "Schweig-Edgard" } ], "thesis_advisor": [ { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "thesis_committee": [ { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Keller", "given_name": "Herbert Bishop", "clpid": "Keller-H-B" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "In this thesis, we analyze high-permittivity dielectric waveguides for use as guiding structures of millimeter waves. Two basic geometries are considered: the circular and rectangular guides.
\r\n\r\nIn Part I, we describe the theory of round fibers surrounded by an infinite cladding. Millimeter wavelengths are comparable to the physical dimensions of the guide. Therefore, a large difference in permittivity between the core and the cladding is required in order to provide for a tight confinement of the fields. We present the results of computations of the propagation characteristics and losses of fibers of very high permittivity. We note that the distribution of the electromagnetic power between the core and the cladding can be deduced from the dispersion curves. Finally, we consider the feasibility of a dielectric fiber made of thallium bromide-iodide (KRS-5) for the long distance transmission of W-band signals (94 GHz). Using our measurements of the dielectric parameters of KRS-5, we find that the losses are several orders of magnitude higher than the losses of conventional metallic waveguides.
\r\n\r\nIn Part II, we analyze rectangular dielectric guides made of high-permittivity materials such as GaAs that would permit the fabrication of active devices directly into the transmission line. We present a new numerical technique base on finite-differences for computing the modes of dielectric guiding structures. This method is simple and efficient in computer storage and computational time. We use it to compute the modes of a rectangular dielectric waveguide and compare the numerical results to those obtained from Marcatili's closed-form solution. We find that this latter one is a good approximation for the dominant mode of a rectangular guide even when the permittivity of the guide is large compared to the outer medium. For higher order modes, Marcatili's solution predicts incorrect propagation curves. We have also observed the presence in our numerical solution of \"spurious modes\" that are thought to be due to the mathematical indefinitiveness of the problem.
\r\n\r\nIn Part III, we present a waveguide technique for the measurement of complex dielectric constants at millimiter wave frequencies: the shorted-waveguide method. Waveguide methods have been extensively used at lower frequencies but this is the first application at 94 GHZ. We use a novel sample preparation technique that allows for an accurate and gap-free positionment of a ductile dielectric material inside a metallic waveguide. We note that the correct choice of sample lengths is critical to the accuracy of the measurement of the loss tangent. Finally, we summarize the results of our measurement of the dielectric constant and loss tangent of thallium bromide-iodide (KRS-5) and thallium bromide-chloride (KRS-6).
", "doi": "10.7907/05DR-KV58", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:10885", "collection": "thesis", "collection_id": "10885", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05142018-171221657", "primary_object_url": { "basename": "Feenstra_RM_1982.pdf", "content": "final", "filesize": 66226037, "license": "other", "mime_type": "application/pdf", "url": "/10885/1/Feenstra_RM_1982.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Electronic and Vibrational States of Point Defects in Semiconductors", "author": [ { "family_name": "Feenstra", "given_name": "Randall Meindert", "clpid": "Feenstra-Randall-Meindert" } ], "thesis_advisor": [ { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" } ], "thesis_committee": [ { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Corngold", "given_name": "Noel Robert", "clpid": "Corngold-N-R" }, { "family_name": "Johnson", "given_name": "William Lewis", "clpid": "Johnson-W-L" }, { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis deals with the properties of defects in tetrahedrally-bonded semiconductors. The detects which will be studied here are impurity atoms substitutional for host atoms in the crystal. In particular, those defects which produce localized electronic states in the middle of the electronic energy gap (\"deep levels\") will be discussed. The main experimental technique used is photoluminescence. The crystals are excited with a laser, and they emit light due to various electronic transitions at the defects. The energy of this luminescence yields information about the nature of the excited electronic states. Also, excited vibrational states of the defects are apparent in the luminescence, and these vibrational states yield structural information about the defect.
\r\n\r\nThe major system studied here is GaP containing Zn and O impurities. The Zn and O ions experience an attractive Coulomb interaction, so that they tend to occupy lattice sites which are near to each other, forming defect pairs. The energy or luminescence emitted from a (Zn,O) pair depends on the separation of the impurities. Thus, a luminescence spectrum contains information about the number or pairs of each possible separation. I have used this phenomenon to monitor the relative positions of Zn and O impurities in the lattice. I have observed reactions in which the impurity atoms move through the lattice under the influence of laser excitation. Specifically, I observe the dissociation of nearest-neighbor (Zn,O) pairs, and the subsequent formation of further separated pairs. The dissociation of the nearest-neighbor pairs can occur thermally, or by a photoinduced mechanism. At temperatures near 200 C, the intensity of the (Zn,O) luminescence spectra changes with time, a direct observation of the photoinduced reactions in progress. The (Zn,O) pairs are observed to dissociate by purely thermal means at temperatures near 900 C. From the rates of these two types of reactions, I identify the photoinduced pair dissociation as being a \"recombination-enhanced defect reaction\". In the reaction, electron-hole recombination puts the defect into a highly excited vibrational state, leading to the dissociation. This is the first observation of this sort of reaction in a system with known defect types. Thus, my study provides unique information about the electron-phonon interaction at defects. This study also has some practical application. The material GaP:(Zn,O) is used for fabricating red light-emitting-diodes, and the dissociation or the pairs provides an explanation for the degradation of these diodes. Presumably the degradation of some other semiconductor devices proceeds by mechanisms similar to those observed here.
\r\n\r\nThis thesis deals with several other topics aside from GaP:(Zn,O). The geometry or impurity pairs in zinc-blende crystals is discussed. For a given separation or the impurity atoms, there is some number or different possible relative orientations of the impurities. I have derived an analytic form for this distribution of impurity pair separations, and I show how this formula can be used to interpret the observed luminescence spectra of GaP:N. Another system studied here is Si containing In and B impurities. Recombination of excitons bound onto the impurities produces luminescence. From the observed decay times of these luminescence lines, I deduce values of the cross sections for free exciton capture onto In and B impurities. The magnitude of the In cross section indicates the presence of excited states of the In bound exciton. Finally, a theoretical treatment of the vibrational modes of substitutional defects in zinc-blende crystals is presented. The defects consist of an impurity atom, with springs or variable strength connecting it to its neighbors. For the case of oxygen in GaP, the theory predicts the existence or two defect vibrational modes, in agreement with experiment. From the energies of the observed vibrational modes, it appears that the oxygen impurity is quite weakly bonded to its neighboring atoms.
", "doi": "10.7907/p5ph-6811", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:9254", "collection": "thesis", "collection_id": "9254", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10282015-112437158", "primary_object_url": { "basename": "Meins_ck_1982.pdf", "content": "final", "filesize": 22803253, "license": "other", "mime_type": "application/pdf", "url": "/9254/1/Meins_ck_1982.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Investigations into Electronic Stopping Regime Sputtering of Uranium Tetrafluoride", "author": [ { "family_name": "Meins", "given_name": "Charles Kenneth, Jr.", "clpid": "Meins-Charles-Kenneth-Jr" } ], "thesis_advisor": [ { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" } ], "thesis_committee": [ { "family_name": "Pine", "given_name": "Jerome", "clpid": "Pine-J" }, { "family_name": "Haff", "given_name": "Peter K.", "clpid": "Haff-P-K" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" }, { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "Yields were measured for 235U sputtered from UF4 by 16O, 19F, and 35Cl over the energy range ~.12 to 1.5 MeV/ amu sing a charge equilibrated beam in the stripped beam arrangement for all the incident ions and in the transmission arrangement for 19F and 35Cl. In addition, yields were measured for 19F incident in a wide range of discrete charge states. The angular dependence of all the measured yields were consistent with cos\u028b. The stripped beam and transmission data were well fit by the form (Az2eqln(B\u0190)/\u0190)4 (where \u0190 was the ion energy in MeV/amu and zeq(\u0190) was taken from Zeigler (80). The fitted values of B for the various sets of data were consistent with a constant B0, equal to 36.3 \u00b1 2.7, independent of incident ion. The fitted values of A show no consistent variation with incident ion although a difference can be noted between the stripped beam and transmission values, the transmission values being higher.
\r\n\r\nThe incident charge data were well fit by the assumptions that the sputtering yield depended locally on a power of the incident ion charge and that the sputtering from the surface is exponentially correlated to conditions in the bulk. The equilibrated sputtering yields derived from these data are in agreement with the stripped beam yields.
\r\n\r\nIn addition, to aid in the understanding of these data, the data of Hakansson (80,81a,81b) were examined and contrasted with the UF4 results. The thermal models of Seiberling (80) and Watson (81) were discussed and compared to the data.
\r\n\r\n", "doi": "10.7907/vsb2-2g34", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:3536", "collection": "thesis", "collection_id": "3536", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09142006-111227", "type": "thesis", "title": "Investigations of Near-Zone Doppler Effects", "author": [ { "family_name": "Prouty", "given_name": "Dale Austen", "clpid": "Prouty-Dale-Austen" } ], "thesis_advisor": [ { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" } ], "thesis_committee": [ { "family_name": "Wilts", "given_name": "Charles Harold", "clpid": "Wilts-C-H" }, { "family_name": "Papas", "given_name": "Charles Herach", "clpid": "Papas-C-H" }, { "family_name": "Phillips", "given_name": "Thomas G.", "clpid": "Phillips-T-G" }, { "family_name": "Psaltis", "given_name": "Demetri", "orcid": "0000-0003-4684-8800", "clpid": "Psaltis-D" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Far away from an electromagnetic source the normal Doppler shifts in frequency occur \u2013 a red shift for receding and a blue shift for approaching. As indicated by previous work with an infinitesimal dipole, different frequency shifts occur when the source and observer move closer together, into the near-zone. These \"near-zone Doppler effects\" are investigated for general sources and subsequently two specific examples are presented.
\r\n\r\nThe general results show that near-zone shifts are similar to far-zone shifts, but the local phase velocity must be used, i.e. \u03c9' \u2243 \u03c9(1 \u00b1 (v/vph)). In the far zone the phase velocity is the speed of light; in the near zone it differs. Fundamentally, the distance between surfaces of constant phase in the near zone is changed. The surfaces of constant phase for the waves are no longer spherical, but more ellipsoidal or spheroidal, so that a moving observer sees a different frequency shift.
\r\n\r\nTwo specific examples are presented to indicate the actual magnitude of near-zone effects. The examples include a prolate spheroidal antenna and a circular aperture.
\r\n\r\nOnce the magnitude of the effects is determined, the measurability of near-zone Doppler effects is discussed. The investigation concentrates on Fresnel zone effects due to the measurement problem.
\r\n\r\nFinally, it is shown that for an electrically large wire antenna (the spheroidal example) near-zone Doppler effects are measurable.
", "doi": "10.7907/vfzj-7d74", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:4566", "collection": "thesis", "collection_id": "4566", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-11152004-162115", "type": "thesis", "title": "The Luminescent Solar Concentrator", "author": [ { "family_name": "Batchelder", "given_name": "John Samuel", "clpid": "Batchelder-John-Samuel" } ], "thesis_advisor": [ { "family_name": "Zewail", "given_name": "Ahmed H.", "clpid": "Zewail-A-H" } ], "thesis_committee": [ { "family_name": "Zewail", "given_name": "Ahmed H.", "clpid": "Zewail-A-H" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "The Luminescent Solar Concentrator (LSC) allows sunlight to be concentrated through the use of light pipe trapping of luminescence. Such concentrators do not require tracking, and they can reduce the cost of solar energy conversion by reducing the required area of photovoltaic cells. We have conducted the following experimental and theoretical investigations in order to optimize the LSC's performance.
\r\n\r\nThe spectral characteristics of 18 organic laser dyes are studied for their applicability as luminescing centers. The spectral homogeneity and self-absorption characteristics of representative dyes are examined in detail. The relative spectral homogeneity of such dyes is shown to depend upon the surrounding material using narrow band laser excitation. We develop three independent techniques for measuring self-absorption rates; these are time-resolved emission, steady state polarization anisotropy, and spectral convolution. Prototype devices are tested for performance, and the componant dyes are tested for stability to solar exposure.
\r\n\r\nA model is developed which predicts the efficiency and gain of and LSC from the spectroscopic characteristics of its components. A critical optical density (CODE) is assigned to the dyes surveyed which predicts the self-absorption limited performance for a particular dye. The maximum efficiency of an LSC is found using a simple model and the experimentally measured Stokes shift required to minimize self-absorption.
\r\n\r\nWe find that the performance of LSCs which achieve high light concentration is primarily limited by self-absorption and by photodegradation. The maximum efficiency possible is about 9% in such systems, and present devices can achieve about 3%. A typical lifetime for an LSC using organic laser dyes due to photodegradation is on the order of a month.
", "doi": "10.7907/W5W7-9660", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:52", "collection": "thesis", "collection_id": "52", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01072005-145115", "type": "thesis", "title": "AlGaAs Optoelectronic Devices for Optical Communications", "author": [ { "family_name": "Katz", "given_name": "Joseph", "clpid": "Katz-Joseph" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "thesis_committee": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Peck", "given_name": "Charles W.", "clpid": "Peck-C-W" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Rauch", "given_name": "Lawrence L.", "clpid": "Rauch-Lawrence-L" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis describes several semiconductor injection laser diodes and related optoelectronic devices that can be used as light sources for optical communication systems, and develops the intrinsic electrical model of the laser diode. All the devices were grown from the GaAs-GaAlAs ternary system using the liquid phase epitaxy technique. The AlGaAs materials are very useful for the fabrication of both optical devices (sources and detectors) and conventional electronic components, due to their optical and electrical properties.
\r\n\r\nThe first device is the Translaser, a monolithically integrated heterostructure bipolar transistor with an injection laser. The next two types of devices possess bistable electrical characteristics. One is a laser-SCR switch, and the second type consists of multi-PN heterostructure devices. Each of the devices described above performs an electronic function, of modulating the light output of the laser associated with it.
\r\n\r\nFinally, two types of low-threshold single-node laser diodes are presented. Their properties make them attractive candidates for sources in optical fiber communication systems. The first one is the Embedded Stripe Laser, and the second one is a new version of the Buried-Heterostructure laser, fabricated on semi-insulating substrates.
\r\n\r\nAn equivalent circuit of the laser diode is presented in the last chapter. This model provides a better understanding of the operation of the laser diode, which is particularly important in applications which involve its high frequency: operation with other electronic components and when a modification of its frequency response is needed.
\r\n", "doi": "10.7907/2AXD-2Z75", "publication_date": "1981", "thesis_type": "phd", "thesis_year": "1981" }, { "id": "thesis:4009", "collection": "thesis", "collection_id": "4009", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-10102006-093346", "type": "thesis", "title": "Theoretical Studies of the Nonlinear Infrared Properties of p-Type Semiconductors", "author": [ { "family_name": "James", "given_name": "Ralph Boyd", "clpid": "James-Ralph-Boyd" } ], "thesis_advisor": [ { "family_name": "Smith", "given_name": "Darryl L.", "clpid": "Smith-D-L" } ], "thesis_committee": [ { "family_name": "Smith", "given_name": "Darryl L.", "clpid": "Smith-D-L" }, { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Dimotakis", "given_name": "Paul E.", "clpid": "Dimotakis-P-E" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "This thesis presents theoretical studies of the nonlinear optical properties of p-type semiconductors. Chapter 2 is concerned with the intensity dependence of the complex dielectric constant of p-type germanium for light with a wavelength in the 9-11 \u00b5m region. The nonlinear absorption is described by the imaginary part of the complex dielectric constant, and the nonlinear dispersive properties are described by the intensity dependence of the real part of the dielectric constant. Chapter 3 deals with the saturation characteristics of practically all Groups IV and III-V p-type semiconductors and includes a discussion of the systematic dependence of the saturation intensity on the material parameters. Chapters 4 and 5 are concerned with several \"pump-and-probe\" experiments. Here, the transmission of a low-intensity light beam (probe) can be altered by the presence of a high-intensity laser (pump). In these chapters the modulation of the probe transmission is analyzed as a function of the intensity of the pump laser. Chapter 6 treats the intensity dependence of the conductivity of p-Ge for light with a wavelength of 10.6 \u00b5m.
\r\n\r\nIn Chapter 2, we present a theory of the saturation of heavy- to light-hole band transitions in p-type germanium by high-intensity light with a wavelength near 10 \u00b5m. The free-hole distribution function is modified by the high-intensity light, which leads to an intensity dependence in the absorption coefficient and the index of refraction. The absorption coefficient is found to decrease with intensity in a manner closely approximated by an inhomogeneously broadened two-level model. For temperatures and hole concentrations where hole-phonon dominates hole-impurity and hole-hole scattering, the saturation intensity is independent of the hole concentration. For larger hole densities, the saturation intensity is found to increase monotonically with increasing hole concentration. We calculate the saturation intensity as a function of excitation wavelength and temperature for p-Ge. The saturation intensity is found to increase with increasing photon energy and temperature. The calculated results for the absorption saturation are compared with the available experimental data and good agreement is found. In addition to the nonlinear absorption, there exist laser-induced changes in the index of refraction resulting from the saturation of the intervalence-band transitions. Calculations of the intensity dependence of the real part of the dielectric constant are performed for room temperature and for light with a wavelength of 10.6 \u00b5m. The index of refraction is found to increase monotonically with increasing intensity.
\r\n\r\nIn Chapter 3, we present the results of the theory describing the saturation behavior of most p-type semiconductors with the diamond or zincblende crystal structure by high-intensity CO2 light. For materials with large spin-orbit splittings as compared to the excitation wavelength (as for Ge), the dominant absorption mechanism is direct intervalence-band transitions where a free hole in the heavy-hole band absorbs a photon and makes a transition to the light-hole band. For materials with small spin-orbit splittings as compared to the excitation wavelength (as for Si), direct intervalence-band transitions are allowed between the heavy-hole and light-hole, heavy-hole and split-off, and light-hole and split-off hole bands. In each material, values of the saturation intensity are reported as a function of the photon energy and temperature.
\r\n\r\nIn Chapter 4, we present a theory to describe the enhanced transmission of a weak tunable probe laser with a wavelength near 3 \u00b5m in the presence of a high-intensity saturating beam with a wavelength near 10 \u00b5m in p-Ge. The mechanism responsible for the increasing transmission of the probe laser is the depletion of holes in the heavy-hole band by the saturating beam. Room temperature values of the absorption coefficient of the probe are predicted as a function of the intensity of the pump beam.
\r\n\r\nIn Chapter 5, we present a theory of the absorption lineshape of a low-intensity probe laser which is tuned in the vicinity of a high-intensity pump laser with a wavelength of 10.6 \u00b5m. Values for the absorption coefficient of the probe are calculated at room temperature as a function of the intensity of the pump laser. We find the probe absorption can be divided into two contributions: one being due to the depletion of holes in the resonant region of the heavy-hole band by the saturable pump, and the other being due to a coupling of the pump and probe beams which allow the pump photons to be scattered into the probe and vice versa. The calculated results for the composite lineshape of the probe are compared with the experimental data and good agreement is found.
\r\n\r\nIn Chapter 6, we show how the modification of the free hole distribution function by the saturating beam leads to a change in the conductivity of p-Ge. The photoconductive response is calculated as a function of the doping level, temperature and light intensity.
", "doi": "10.7907/e2ha-tt71", "publication_date": "1981", "thesis_type": "phd", "thesis_year": "1981" }, { "id": "thesis:3621", "collection": "thesis", "collection_id": "3621", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09182006-141505", "type": "thesis", "title": "(AlGa)As Semiconductor Lasers and Integrated Optoelectronics", "author": [ { "family_name": "Wilt", "given_name": "Daniel Paul", "clpid": "Wilt-Daniel-Paul" } ], "thesis_advisor": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" } ], "thesis_committee": [ { "family_name": "Yariv", "given_name": "Amnon", "clpid": "Yariv-A" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "Five subjects related to monolithic integration of electronic and optical devices in the (AlGa)As material system are treated in this thesis. They are:
\r\n\r\n1. The Integrated Optoelectronic Repeater:
\r\n\r\nThe design, fabrication, and testing of the first monolithic integrated optical repeater is described. This device consists of an optical detector, electronic gain stage, and current modulated semiconductor laser transmitter integrated in a single crystal chip to perform the function of regenerating an optical signal as might be found in an optical communication system. The device has a measured optical gain (light out to light in) of 10 dB.
\r\n\r\n2. Ion Implanted Lasers and Schottky Gate Field Effect Transistors:
\r\n\r\nThe use of ion implantation as a technique to fabricate both lasers and field effect transistors is described. Devices fabricated include a beryllium implanted laser diode on N type GaAs substrate, a beryllium implanted laser diode on semi-insulating Cr doped GaAs substrate integrated with a field effect transistor driver, and sulfur implanted GaAs field effect transistors.
\r\n\r\n3. A Steady State Lateral Model of the Double Heterostructure Laser:
\r\n\r\nA theoretical model of the double heterostructure laser is described which treats the p-n junction in the device correctly by using fundamental semiconductor relationships and reasonable assumptions about the device heterointerfaces. The model treats both the electronic and optical properties self consistently, making the model valid above lasing threshold. Finite element formalism is adopted as a solution technique to enable the treatment of complicated diode geometries. An example is treated and theoretical and experimental results are compared.
\r\n\r\n4. The Effect of Lateral Carrier Diffusion on the Modulation Response of a Semiconductor Laser:
\r\n\r\nThe effect of lateral carrier diffusion upon the modulation characteristics of the semiconductor laser is investigated. A self consistent analysis of the spatially dependent rate equations is performed using a finite element model. The transverse junction stripe laser is treated as an example and a comparison is made between lateral carrier diffusion and spontaneous emission as damping mechanisms for the resonance peak. Experimental results bear out the conclusion that the relaxation resonance in this device is damped mainly by lateral carrier diffusion. In addition, a simple analytic result is presented which illustrates qualitatively the effect of lateral carrier diffusion upon such devices. The conclusion from this result is that lateral carrier diffusion serves to damp the relaxation resonance in the semiconductor laser quite well, but probably will not serve to improve the upper limit on modulation frequency as might have been suspected.
\r\n\r\n5. Effective Permittivity Formalism and the Design of Buried Heterostructure Lasers:
\r\n\r\nAn approach to effective permittivity formalism is presented which clarifies and extends the use of this technique particularly in the treatment of waveguiding in the semiconductor laser. The scalar wave equation is posed in a variational form, and the effective permittivity formalism is treated as a variational approximation technique. This approach shows clearly the nature and limits of the approximation involved. The formalism is applied to the case of the buried heterostructure laser and the results differ considerably from the conventional application of effective permittivity formalism to this device when a reasonable form is assumed for the variational modal profile.
", "doi": "10.7907/f9jz-ez68", "publication_date": "1981", "thesis_type": "phd", "thesis_year": "1981" }, { "id": "thesis:6066", "collection": "thesis", "collection_id": "6066", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:09282010-100527331", "primary_object_url": { "basename": "Gabriel_ak_1981.pdf", "content": "final", "filesize": 5260594, "license": "other", "mime_type": "application/pdf", "url": "/6066/1/Gabriel_ak_1981.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Optogalvanic Spectroscopy and Cataphoretic Laser Isotope Separation", "author": [ { "family_name": "Gabriel", "given_name": "Andrew Keith", "clpid": "Gabriel-Andrew-Keith" } ], "thesis_advisor": [ { "family_name": "Shair", "given_name": "Fredrick H.", "clpid": "Shair-F-H" } ], "thesis_committee": [ { "family_name": "Shair", "given_name": "Fredrick H.", "clpid": "Shair-F-H" }, { "family_name": "Bridges", "given_name": "William B.", "clpid": "Bridges-W-B" }, { "family_name": "Bellan", "given_name": "Paul Murray", "orcid": "0000-0002-0886-8782", "clpid": "Bellan-P-M" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Culick", "given_name": "Fred E. C.", "clpid": "Culick-F-E-C" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "A microscopic theory for the positive column discharge (PCD) is developed using rate equations and power balance equations to model the microscopic discharge processes. Macroscopic variables are calculated from the microscopic parameters. The model is used to characterize a hydrogen-helium PCD.
\r\n\r\nThe equations in the model are modified to account for the presence of resonant (H-alpha) radiation from an external source. The model is then used to predict the voltage change in a hydrogen PCD (the optogalvanic effect) as a function of current, illumination intensity, and gas pressure. The results compare very favorably with experiments conducted to measure the OGE.
\r\n\r\nTransient voltage changes induced by resonant illumination in a PCD are calculated by numerical integration of the model equations. Perturbation theory is applied to the equations to obtain more physical insight into the physics of the transient OGE.
\r\n\r\nThe experimental apparatus used to measure the OGE and that used to measure the electron temperature (double probes) are described. A discussion of experimental problems covers some of the difficulties encountered.
\r\n\r\nThe PCD model and OGE model are used to evaluate the practicality of separating hydrogen and deuterium by optically assisted cataphoresis in the PCD.
\r\n\r\nThe possibility that recombination is a dominant process in the discharge is discussed in detail and rejected.
\r\n\r\nA careful description of the interaction of the illuminating radiation and the PCD plasma is given, with special attention to homogeneous and inhomogeneous broadening processes, saturation of absorption and saturation of the OGE, and the relative bandwidths of the illuminating radiation and discharge gas.
\r\n\r\nSome suggestions are made for future work.
", "doi": "10.7907/xhjf-aa40", "publication_date": "1981", "thesis_type": "phd", "thesis_year": "1981" }, { "id": "thesis:4964", "collection": "thesis", "collection_id": "4964", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-12122006-090129", "type": "thesis", "title": "Investigations of Schottky Barrier Structures in Compound Semiconductors: I. HgTe on CdTe: a Lattice Matched Schottky Barrier. II. Au-Cd Barriers to CdTe. III. AAu Barriers on In\u2093Ga\u2081\u208b\u2093P", "author": [ { "family_name": "Kuech", "given_name": "Thomas Francis", "clpid": "Kuech-Thomas-Francis" } ], "thesis_advisor": [ { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" } ], "thesis_committee": [ { "family_name": "McCaldin", "given_name": "James Oeland", "clpid": "McCaldin-J-O" }, { "family_name": "Goddard", "given_name": "William A., III", "orcid": "0000-0003-0097-5716", "clpid": "Goddard-W-A-III" }, { "family_name": "McGill", "given_name": "Thomas C.", "clpid": "McGill-T-C" }, { "family_name": "Rutledge", "given_name": "David B.", "clpid": "Rutledge-D-B" }, { "family_name": "Nicolet", "given_name": "Marc-Aurele", "clpid": "Nicolet-M-A" } ], "local_group": [ { "literal": "div_eng" } ], "abstract": "i) The Au Schottky barrier height to n - InxGa1-xP was measured as a function of alloy composition. The Au barrier, \u03c6p, to p - InxGa1-xP was found to be independent of composition. The barrier, \u03c6p, was determined by the relation \u03c6p + \u03c6n = \u03c6g where \u03c6g is the band gap energy and \u03c6n is the measured barrier height to n - InxGa1-xP. It has been observed that the Au barrier height to p-type material for most compound semiconductors is determined by the anion. This dependence on the anion of the compound has now been seen to extend to the alloy system InxGa1-xP measured here.
\r\n\r\nii) The Schottky barrier height of Cd, Au, and Au-Cd alloys was determined on vacuum cleaved surfaces of n-CdTe. A large barrier of 0.92 eV was found in the case of the Au-Cd alloy contacts. Contacts made with elemental Cd or Au gave barrier heights of 0.45 and 0.65 eV, respectively. The increased barrier height found on Au-Cd alloy contacts may be related to recent UHV observations on Schottky barrier formation where crystal defects play a role in determining the observed barrier height.
\r\n\r\niii) HgTe-CdTe lattice matched heterojunctions were formed by the epitaxial growth of HgTe on CdTe substrates using a new low temperature metal organic chemical vapor deposition (MOCVD) technique. These heterojunctions combine features of the Schottky barrier structure, due to the high carrier concentrations found in the semi-metallic HgTe, with the structural perfection present in a lattice matched heterojunction. The measured Schottky barrier height varied from 0.65 to 0.90 eV depending on the details of the HgTe growth procedure used. Two models of the HgTe-CdTe heterojunction are presented which account for the observed variation in barrier height.
", "doi": "10.7907/8hcw-7421", "publication_date": "1981", "thesis_type": "phd", "thesis_year": "1981" } ]