Wan Shan Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract / Acknowledgements / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- History of Semiconductor Optical Amplifier In Optical Networks --- p.1 / Chapter 1.2 --- Comparisons of SOAs With Other Amplifiers --- p.3 / Chapter 1.2.1 --- Erbium Doped Fiber Amplifier (EDFA) --- p.3 / Chapter 1.2.2 --- Raman Amplifiers --- p.5 / Chapter 1.2.3 --- Parametric Amplifiers --- p.7 / Chapter 1.3 --- The Need of SO A for Wavelength Conversion in Optical Networks --- p.8 / Chapter 1.3.1 --- General Applications of SOAs --- p.8 / Chapter 1.3.2 --- Wavelength Conversion of SOAs --- p.9 / Chapter 1.4 --- Cross Gain Modulation (XGM) --- p.11 / Chapter 1.5 --- Cross Phase Modulation (XPM) --- p.13 / Chapter 1.6 --- Four Wave Mixing (FWM) --- p.16 / Chapter 1.7 --- Bi-refringence Switching --- p.19 / Chapter 1.8 --- Conclusion --- p.22 / Chapter 1.9 --- References --- p.22 / Chapter Chapter 2 --- Physics of Semiconductor Optical Amplifier and Background of Quantum Well Semiconductor Optical Amplifier / Chapter 2.1 --- Physics of Semiconductor Optical Amplifier --- p.26 / Chapter 2.1.1 --- General Structure of SOAs --- p.26 / Chapter 2.1.2 --- Principles of Optical Amplification --- p.27 / Chapter 2.1.3 --- Material Gain Coefficient --- p.29 / Chapter 2.1.4 --- Bulk Material Properties of SOAs --- p.32 / Chapter 2.1.5 --- Spontaneous Emission Noise --- p.34 / Chapter 2.1.6 --- Polarization Sensitivity --- p.37 / Chapter 2.1.7 --- Dynamics Effects --- p.38 / Chapter 2.2 --- Background of Quantum Wells Semiconductor Optical Amplifier --- p.38 / Chapter 2.2.1 --- Definition of Quantum Well SOAs --- p.38 / Chapter 2.2.2 --- Different Types of Quantum Well SOAs --- p.39 / Chapter 2.2.3 --- Quantization of the Conduction Band and Valence Band --- p.40 / Chapter 2.3 --- Comparison Between Bulk and Quantum Well SOAs --- p.44 / Chapter 2.3.1 --- Gain Bandwidth --- p.44 / Chapter 2.3.2 --- Polarization Dependence --- p.44 / Chapter 2.3.3 --- Saturation Output Power --- p.45 / Chapter 2.4 --- Conclusion --- p.46 / Chapter 2.5 --- References --- p.46 / Chapter Chapter 3 --- Wideband Wavelength Conversion by XGM in Asymmetrical Multiple Quantum Well Semiconductor Optical Amplifier (AMQW-SOA) / Chapter 3.1 --- Background of Wideband Asymmetrical Multiple Quantum Well Semiconductor Optical Amplifier --- p.47 / Chapter 3.1.1 --- Sequence Influence of Non-identical InGaAsP Quantum Wells on SO A Broadband Characteristics --- p.47 / Chapter 3.1.2 --- Influence of Separate Confinement Heterostructure on Emission Bandwidth InGaAsP SOAs --- p.54 / Chapter 3.2 --- Wideband Wavelength Conversion --- p.58 / Chapter 3.2.1 --- First Experiment of Wideband Wavelength Conversion from 1.5 μm to 14 μm by XGM in AMQW-SOA --- p.62 / Chapter 3.2.2 --- Second Experiment of Wideband Wavelength Conversion from 1.5 μm to 1.4μm by XGM with 2.5 Gbit/s in AMQW-SOA --- p.64 / Chapter 3.2.3 --- Third Experiment of Investigation of Wavelength Conversion from 15 μm to 1.5 μm/1.3 μm by XGM in AMQW-SOA --- p.67 / Chapter 3.3 --- Conclusion --- p.69 / Chapter 3.4 --- References --- p.71 / Chapter Chapter 4 --- Wavelength Conversion by Birefringence Switchingin Asymmetrical Multiple Quantum Well Semiconductor Optical Amplifier (AMQW-SOA) / Chapter 4.1 --- First Experiment of Wideband Wavelength Conversion from 1.5 μm to 1.4 μm by Birefringence Switching in AMQW-SOA --- p.74 / Chapter 4.2 --- Second Experiment of Investigation of Wavelength Conversion from 1.5 μm to 1.5μm by Birefringence Switching in AMQW-SOA --- p.76 / Chapter 4.3 --- Conclusion --- p.78 / Chapter 4.4 --- References --- p.79 / Chapter Chapter 5 --- Asymmetrical Multiple Quantum Well Semiconductor Optical Amplifier (AMQW-SOA) for Pattern-Effect Free Gain / Chapter 5.1 --- Examples Methods of Pattern Effect Compensation --- p.81 / Chapter 5.1.1 --- Suppression of Pattern Dependent Effects from a Semiconductor Optical Amplifier using an Optical Delay Interferometer (ODI) / Chapter 5.1.2 --- Acceleration of Gain Recovery in QD-SOA --- p.84 / Chapter 5.2 --- Background Theory of Quantum Well Reservoirs and Carrier Transit Time --- p.87 / Chapter 5.3 --- First Experiment of Pattern Effect Free Amplification in AMQW-SOA --- p.92 / Chapter 5.4 --- Second Experiment of Pattern Effect Free Amplification in AMQW-SOA --- p.97 / Chapter 5.5 --- Conclusion --- p.102 / Chapter 5.6 --- References --- p.103 / Chapter Chapter 6 --- Conclusion and Future Work / Chapter 6.1 --- Conclusion --- p.105 / Chapter 6.2 --- Future Work --- p.108 / Appendix Butterfly Photonic Packaging --- p.109

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 123-126).

Metasurfaces are nanostructured interfaces capable of manipulating the phase, amplitude, or polarization of free-space light. ‘Local’ metasurfaces typically control the wavefront shape of spectrally broadband light to generate devices such as flat lenses, holograms, and beam steerers. In contrast, ‘nonlocal’ metasurfaces, such as photonic crystals, support spatially-extended optical modes that govern the transmission or reflection spectrum. Therefore, local metasurfaces typically offer spatial control over incident light but not spectral control, while nonlocal metasurfaces impose spectral but not spatial control. This thesis explores nonlocal dielectric metasurfaces with simultaneous spatial and spectral control such that they shape the wavefront only for spectrally narrowband resonant modes but act like an unpatterned substrate for non-resonant light. These devices are formulated from a rational design scheme based on symmetry arguments. Chapter 1 reviews the theoretical basis for these devices. Chapters 2 and 3 discuss experimental demonstrations of nonlocal wavefront-shaping metasurfaces in the near-infrared and visible wavelength regions, respectively. Our initial experimental demonstrations in the near-infrared in silicon metasurfaces were the first verification of their theoretical proposal. In the visible, experimental results of metasurfaces made of silicon-rich silicon nitride suggest potential applications in transparent displays, augmented reality headsets, and quantum optics. Significantly, our nonlocal metasurfaces form a versatile platform for multifunctional and multicolor meta-optics that shape the wavefront distinctively at several different resonant wavelengths, which we have experimentally demonstrated in both the near-infrared and the visible. Chapters 4 and 5 discuss conceptualization and experimentally demonstration of thermally-tunable nonlocal wavefront-shaping metasurfaces. Reconfigurable photonic devices such as zoom lenses and dynamic holograms have posed a substantial challenge and captured the interest of the optics community. We leverage the enhanced light-matter interaction in our nonlocal wavefront-shaping metasurfaces to realize tunable wavefront-shaping using conventional dielectric materials and standard nanofabrication procedures. The operating principle of these devices is that tuning the refractive index of the device with the thermo-optic effect can align or detune the resonant wavelength of a mode from the wavelength of a narrowband incident light source, and the wavefront is shaped only when the optical resonance is spectrally aligned with the incident light. Experimentally, we have demonstrated nonlocal metasurfaces based on structured germanium thin films whose functionality can be thermally switched between that of two different lenses. The thesis is concluded with a section on future prospects.

Sensing systems for mid-infrared wavelengths (2 to 5 μm) have important applications in biomedical, atmospheric and process gas monitoring systems. For lack of a suitable substrate, the full potential of GaSb-based materials, which are particularly suitable for operating in these wavelengths, are not completely realized. Hence, metamorphic growth technology, that allows the growth of semiconductor epilayers of arbitrary composition on any substrate, has been explored for antimony materials in this research. This makes the growth of device layers, containing arbitrary composition of GaSb-based materials, possible on commercially available 6"-GaAs substrates, and thereby reducing fabrication cost. Metamorphic growth of In(0.15)Ga(0.85)Sb was achieved using gas-source molecular beam epitaxy by growing compositionally graded ln(x)Ga(1-x)Sb buffer layers on a GaSb substrate. The effects of growth temperature on the quality of the metamorphic buffer layers along with the etching issues (both wet and dry) of GaSb-based materials were studied. Homo-junction n-i-p and p-i-n diodes were fabricated on In(0.15)Ga(0.85)Sb metamorphic layers. The dark current and its temperature dependence were measured and the extraction of area and perimeter components of dark current was done. The modeling of the components of dark current suggests that the diode currents were dominated by surface leakage. Surface passivation by silicon nitride and polyimide were investigated and our findings suggest that the former resulted in a better passivated surface. Responsivity measurements show that In(0.18)Ga(0.82)Sb diodes, metamorphically grown on GaSb substrates, have a cut-off wavelength of 2270 nm. Finally, hole (β) and previously unreported electron (α) ionization coefficients, at room temperature and 90° C, were extracted from these structures. The results show that α>β for ln(0.10)Ga(0.90)Sb for both temperatures. These photodetectors can be implemented m practical receiver systems for mid-infrared applications, such as atmospheric CO2 and methane detection at 2.0 μm. The possibility of growing antimony-based device layers on larger substrates, paves the way for future optoelectronic receiver systems operating at longer wavelengths, where both the photodetector and the amplifier can be integrated in the same module. / Thesis / Doctor of Philosophy (PhD)

In recent years, there has been significant progress in the development of integrated photonic circuits (PICs). Matured fabrication and simulation techniques have enabled the development of novel devices and system architectures. Ideally, these newly developed technologies are put to test in the lab, both to verify that they perform as simulated and to demonstrate the viability of the technology. Testing the increasingly complex optical circuits brings various challenges. One of these challenges is the sensitivity to temperature changes of many optical circuits, especially micro ring and micro disk resonators (MRRs and MDRs). Due to the nature of these resonators, slight deviations in the material properties have a large impact on their resonant frequency. Despite this, their small footprint and wavelength selectivity makes them promising components for many future technologies, especially Dense Wavelength Division Multiplexed (DWDM) communication links. Multiple resonators cascaded on a single bus waveguide can operate on multiple wavelengths simultaneously with relatively few components and in a small combined area. Since every extra connection to a PIC has a footprint similar to that of a micro resonator, a packaging optimized thermal control scheme is needed to fully leverage all advantages of micro resonators. This work will focus on the thermal stabilization of cascaded micro resonators and how thermal control can be optimized to simplify the packaging of PIC prototypes. This simplification enables the demonstration of complex systems and more realistic scenarios for thermal control of both resonators and other circuits. It will first show how a number of PICs and their respective packages were built, keeping subsequent testing in mind. Then, it demonstrates automatic initialization of cascaded MRR and how stable operation, while undergoing large temperature swings, can be achieved using a minimum number of connections to the PIC. Next, it shows stable operation of an eight-wavelength receiver, operating uncooled at 16 Gb/s/?, over a record 75 °C. Finally, it presents how all the learned lessons are brought together to built a 2.5D integrated SiPh transceiver that is capable of transmitting 512 Gb/s bidirectionally. This transceiver can be plugged into Field Programmable Gate Arrays (FPGAs), which can then be used to implement accelerators for real computing problems, used as a PCIe bridge to a standard compute server, or both. The transceiver is also designed to work with many types of optical switches, allowing demonstrations of novel switching algorithms and network architectures. The contributions discussed in this thesis can assist in enabling future high bandwidth optical interfaces by optimizing the thermal control strategy and may be used at all stages of PIC design and packaging to facilitate the development of new technologies.

No description available.

This thesis concerns technical aspects related to the design and operation of the submillimetre common-user bolometer array 2 (SCUBA-2) instrument, a new wide-field camera for submillimetre astronomy currently undergoing commissioning on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. Offering unprecedented sensitivity and mapping capabilities, SCUBA-2 is expected to make a major impact in surveys of the sky at submillimetre wavelengths, a largely unexplored part of the electromagnetic spectrum, and provide better understanding of the formation and evolution of galaxies, stars and planets by providing large, unbiased samples of such objects. SCUBA-2 uses large arrays of bolometers, with superconducting transition edge sensors (TESs) as the temperature-sensitive element. TES devices are a relatively new technology, utilising the sharp resistance change between the normal and superconducting states to make a sensitive thermistor. Kilopixel arrays of such devices are multiplexed using superconducting quantum interference devices (SQUIDs). This thesis derives the key detector performance parameters, and presents analysis of engineering data to confirm the detector performance on array scales. A key issue for bolometric instruments for far infrared and submillimetre astronomy is the need to operate at extremely low temperatures in the sub-kelvin and millikelvin ranges to achieve the necessary detector sensitivity. This work describes the design, testing and performance of the liquid cryogen-free millikelvin cryostat, the first such instrument to be deployed for astronomy. Subsequent chapters detail the design and testing of a magnetic shielding scheme for the instrument, an important aspect of the operation of superconducting devices. Based on experience with the construction and testing of this instrument, a number of potential improvements for future instruments are presented and discussed.

19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2082" Henry Hao-Chuan Kang. 12/19/2004. Report is also available in paper and microfiche from NTIS.

Made available in DSpace on 2014-10-09T12:28:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:04Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP; Faculdade de Odontologia, Universidade de Sao Paulo, Sao Paulo

Made available in DSpace on 2014-10-09T12:33:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:39Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP