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This thesis explores the possible gains and discusses the constraints of a communications system that uses a ship to unmanned aerial vehicle (UAV) radio frequency (RF) link paired with a UAV to satellite free space optic (FSO) link to accomplish satellite communications. Analysis shows that a data rate of 2 gigabits per second (Gbps) with a 1 . 10 probability of bit error can be attained by a shipboard system with a relatively small antenna and power supply if an FSO-enabled UAV is used. An experiment demonstrated that the addition of an FSO link and additional routing does not reduce the performance of a slower data rate RF link. The findings indicate that a composite RF and FSO ship-UAV-satellite system can be used within the Transformational Communications Architecture (TCA) and with the Navy's FORCEnet to enable network-centric operations (NCO).

M.Ing. / Optical fibre Bragg gratings are a periodic variation of the refractive index in the core of an optical fibre andmay be formed by exposure to intense UV laser light under specific conditions. Light at a certain wavelength, called the Bragg wavelength, is reflected back when illuminating the grating with a light source. Bragg gratings can relatively easily be employed as strain and temperature sensors, but have small sensitivity for pressure. Special transducers are required to increase the sensitivity. A pressure sensor was manufactured by coating a fibre Bragg grating with a polymer. The polymer coating converts transverse pressure into longitudinal strain through the Poisson effect inside the polymer coating. This thesis investigates the sensitivity of themanufactured Bragg grating pressure sensor, by using the method of finite element analysis. An account of the experimental setup, whereby the Bragg grating is written with a frequency tripled Nd:YAG laser, is given. The process whereby the fibre is coated with the polymer is described. The sensor is characterized through experimental results and a comparison is made between theoretical and experimental results. Uses for this sensor and ways with which the sensitivity may be increased are suggested as future work.

The research in this dissertation was undertaken because of a need for a more accurate, reliable and relatively simple method for determining the combined loading (i.e., axial, flexure and shear) along rock bolts. This combined load determination and understanding also resulted in a relatively simple and reliable new rock bolt design methodology. The new design method was based on a clearer understanding of the actual loading along a grouted rock bolt. To accomplish these research goals, double shear tests were conducted in the lab with reinforced concrete specimens, and field trials were conducted in room and pillar coal mines, with the aim to measure in-situ rock shear. Strain measurements were obtained using rock bolts instrumented with optical fibers that possessed high spatial resolution (≈ 1.25 – 2.5 mm). Corroboration with a past database of rock bolt measurements in shale aided in the deduction of the final support design method. The scientific contributions from this research include the conceptualization of a ground reaction curve that considers time effects such as rock relaxation, long term weakening effects, and lateral rock movement. A new explanation as to why rock bolts creep in practice (i.e., dislocation creep) is described based upon field measurements, which also indicated that the process of in-situ rock shear involves slow episodic movements. Specifically, there are localized compression (i.e., rock pinch) and tensile zones (i.e., dilatation) prior to the occurrence of plastic relief (i.e., rock slip). Finally, the design method is developed using simple factors (i.e., strain and shape factors) and loading conditions (e.g., installed load, rock slip) that occurred throughout the rock bolt’s design life. This approach results in a methodology that considers effects on reinforcement with time and combined loadings. The method is then extended by producing survival and hazard functions for rock bolts to ultimately reduce risk associated with design.

Optical signal processing plays a key role in a high capacity all-optical communication network. Rapid advances in the processing technology offers new solutions to enhance fiber communications. This thesis focuses on the development of new components and techniques for optical signal processing. / The application of optical nonlinearities in fibers and in semiconductor devices is of great importance in different fields of research. In this thesis, we report our findings in the development of new techniques for photonic signal processing. Two different approaches for extinction ratio enhancement of an amplitude-shift keying (ASK) signal have been demonstrated using self-phase modulation in a highly nonlinear bismuth oxide fiber. The differential phase-shift keying (DPSK) modulation format is also receiving much attention owing to its improved receiver sensitivity and its higher tolerance to signal degradation by undesired fiber nonlinearities. We demonstrated all-optical processing of DPSK signals using different nonlinear phenomena in a semiconductor optical amplifiers, a dispersion-flattened highly nonlinear photonic crystal fiber, and a highly nonlinear bismuth oxide fiber. Various application areas including extinction ratio enhancement, amplitude noise reduction, phase noise reduction, wavelength conversion and wavelength multicasting have been realized using four-wave mixing, self-phase modulation, and cross-phase modulation in the optical elements. (Abstract shortened by UMI.) / The birefringent comb filter is an important element in the processing of microwave and optical signals. To increase the flexibility in its operation, it is desirable for the filter to be tunable in both the spectral position and the spacing of the comb. By incorporating an electro-optic phase modulator to control the overall birefringence, the output comb can be rapidly modulated in the spectral domain. We also introduced a new architecture of a dual-pass Lyot filter that offers the highest tunability of the comb spacing at a given number of birefringent fiber elements. Selectivity of the spacing is based on different alignments between the fiber axes in our cascadable scheme. We applied the birefringent comb filter to multi-wavelength laser source generation using either a semiconductor or a fiber-based gain element. By electrical tuning of the birefringence inside a semiconductor optical amplifier ring laser, a waveband switchable multi-wavelength source has been obtained. In an erbium-doped fiber (EDF) laser, multi-wavelength lasing is inhibited at room temperature owing to the homogeneously broadened gain medium. To address this problem, two different types of fiber nonlinearities, stimulated Brillouin scattering and four-wave mixing, are incorporated separately to the EDF laser to provide self-stabilization of the multi-wavelength oscillation. In addition to multi-wavelength source generation, we further applied the birefringent comb filter to multiply the repetition rate of a high-speed pulsed source using the spectral elimination approach. Repetition rate multiplication from 10 to 40 GHz has been simultaneously achieved for four ITU-grid laser sources around 1550 nm, resulting in an aggregate pulse rate of 160 GHz. The phase coherence of the output pulses is also preserved. / Fok, Mei Po Mable. / "August 2007." / Adviser: Chester Shu. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1198. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

by Kit Chan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgment --- p.v / Table of Contents --- p.vi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Ultrashort Pulses Generation in Semiconductor Lasers and Fiber Lasers --- p.2 / Chapter 1.2 --- Wavelength Tunable Pulse Generation From Semiconductor Laser --- p.4 / Chapter 1.3 --- Wavelength Tunable Pulse Generation from Erbium Doped Fiber Lasers --- p.7 / Chapter 1.4 --- Structure of the thesis --- p.8 / Reference --- p.10 / Chapter 2. --- Principles and Theories --- p.14 / Chapter 2.1 --- Principle of Synchronous Injection Seeding --- p.15 / Chapter 2.2 --- Principle of Compensated Dispersive Tuning in Self-seeding Configuration --- p.18 / Chapter 2.3 --- Principle of Compensated Dispersive Tuning in Actively Mode-Locked Fiber Laser --- p.20 / Chapter 2.4 --- Principle of Wavelength Switching in Actively Mode-Locked Fiber Laser with Fiber Bragg Gratings in Cascaded Configuration --- p.24 / Chapter 3. --- Electrical Wavelength Tunable Pulses Generated From Two-way Synchronous Injection Seeded Fabry-Perot Laser Diodes --- p.26 / Chapter 3.1 --- Introduction --- p.27 / Chapter 3.2 --- Experimental Details --- p.28 / Chapter 3.3 --- Results and Discussion --- p.31 / Chapter 3.4 --- Summary --- p.38 / Reference --- p.39 / Chapter 4. --- Compensated Dispersive Tuning In Self-Seeding Configuration --- p.41 / Chapter 4.1 --- Introduction --- p.42 / Chapter 4.2 --- Experimental Details --- p.43 / Chapter 4.3 --- Results and Discussion --- p.46 / Chapter 4.4 --- Summary --- p.55 / Reference --- p.56 / Chapter 5. --- Compensated Dispersive Tuning in Actively Mode-Locked Fiber Laser --- p.57 / Chapter 5.1 --- Introduction --- p.58 / Chapter 5.2 --- Experimental Details --- p.59 / Chapter 5.3 --- Results and Discussion --- p.61 / Chapter 5.4 --- Summary --- p.69 / Reference --- p.70 / Chapter 6. --- Compensated Dispersive Tuning in Actively Mode-Locked Fiber Laser Using Linearly Chirped Fiber Bragg Grating --- p.71 / Chapter 6.1 --- Introduction --- p.72 / Chapter 6.2 --- Experimental Details --- p.73 / Chapter 6.3 --- Results and Discussion --- p.75 / Chapter 6.4 --- Summary --- p.77 / Reference --- p.78 / Chapter 7. --- Electrically Wavelength Switching in Actively Mode- locked Fiber Laser Using Fiber Bragg Gratingsin Cascaded Configuration --- p.79 / Chapter 7.1 --- Introduction --- p.80 / Chapter 7.2 --- Experimental Details --- p.81 / Chapter 7.3 --- Results and Discussion --- p.83 / Chapter 7.4 --- Summary --- p.87 / Reference --- p.88 / Chapter 8. --- Conclusion and Future Works --- p.89 / Chapter 8.1 --- Conclusion --- p.89 / Chapter 8.2 --- Possible Future Works --- p.92 / Appendices --- p.A-l / Chapter Appendix A. --- List of Publications --- p.A-l / Chapter Appendix B. --- List of Figures --- p.A-2

Lee Ka-lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgment --- p.v / Table of contents --- p.vi / List of figure --- p.viii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Generation of picosecond pulses from semiconductor laser and fiber laser --- p.2 / Chapter 1.2. --- Wavelength tunable pulse generated from semiconductor laser --- p.5 / Chapter 1.3. --- Wavelength tunable pulse generated from erbium doped fiber laser --- p.7 / Chapter 1.4. --- Structure of the thesis --- p.8 / Chapter 2. --- Principles and Theories --- p.13 / Chapter 2.1. --- Principle of dispersion tuning --- p.15 / Chapter 2.1.1. --- Dependence on the strength of dispersion --- p.16 / Chapter 2.1.2. --- Wavelength selection in time domain --- p.18 / Chapter 2.1.3. --- Compensated dispersion tuning in a dispersion balanced fiber ring --- p.20 / Chapter 2.2. --- Optical gating using Nonlinear Optical Loop Mirror (NOLM) incorporated with nonlinear element --- p.22 / Chapter 2.3. --- Principle of compensated dispersion tuning in harmonically mode- locked fiber laser incorporated with linearly chirped fiber grating (LCFG) --- p.26 / Chapter 2.4. --- Principle of compensated dispersion tuning in self-seeding configuration --- p.29 / Chapter 2.5. --- Principle of dual-wavelength operation in harmonically mode-locked fiber laser --- p.31 / Chapter 3. --- Preliminarily experimental study --- p.33 / Chapter 3.1. --- Wavelength selection using strong and weak dispersive medium --- p.34 / Chapter 3.2. --- NOLM as a fast optical modulator --- p.38 / Chapter 4. --- Self-compensated dispersion-tuning in mode-locked fiber laser using bi- directional transit in a linearly chirped fiber grating --- p.41 / Chapter 4.1. --- Introduction --- p.42 / Chapter 4.2. --- Experimental Details --- p.43 / Chapter 4.3. --- Results and discussion --- p.47 / Chapter 4.4. --- Summary --- p.54 / Chapter 5. --- Generation of wavelength tunable pulses from a self-seeded semiconductor laser using an optically controlled Nonlinear Optical Loop Modulator (NOLM) incorporated with a Semiconductor Optical Amplifier (SOA) --- p.56 / Chapter 5.1. --- Introduction --- p.57 / Chapter 5.2. --- Experimental Details --- p.58 / Chapter 5.3. --- Results and discussion --- p.64 / Chapter 5.4. --- Summary --- p.71 / Chapter 6. --- Alternate and Simultaneous Generation of 1 GHz Dual-Wavelength Pulses from an Electrically-Tunable Harmonically Mode-locked Fiber Laser --- p.74 / Chapter 6.1. --- Introduction --- p.75 / Chapter 6.2. --- Experimental Details --- p.76 / Chapter 6.3. --- Results and discussion --- p.80 / Chapter 6.4. --- Summary --- p.87 / Chapter 7. --- Conclusion and Future works --- p.89 / Chapter 7.1. --- Conclusion --- p.89 / Chapter 7.2. --- Future works --- p.93 / Appendix --- p.A-l / List of Publication --- p.A-l

by Wai-Shan Chan. / Thesis submitted in: August 1997. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 61-63). / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Fiber recirculating delay loop --- p.2 / Chapter 1.3 --- Slicing scheme --- p.3 / Chapter 1.4 --- Outline of the thesis --- p.4 / Chapter Chapter 2 --- Fiber recirculating delay loop / Chapter 2.1 --- Review --- p.5 / Chapter 2.1.1 --- Introduction --- p.5 / Chapter 2.1.2 --- The device --- p.6 / Chapter 2.1.3 --- Filtering properties of the fiber recirculating delay loop --- p.8 / Chapter 2.1.4 --- Noise properties of the fiber recirculating delay loop --- p.10 / Chapter 2.1.5 --- Limitations of the BRL device --- p.13 / Chapter 2.2 --- Discussion --- p.14 / Chapter 2.3 --- Summary --- p.14 / Chapter Chapter 3 --- Slicing scheme / Chapter 3.1 --- Introduction --- p.16 / Chapter 3.2 --- Slicing Scheme --- p.18 / Chapter 3.3 --- Experimental Investigation --- p.20 / Chapter 3.4 --- Numerical analysis --- p.33 / Chapter 3.5 --- Simulations --- p.40 / Chapter 3.6 --- Discussion --- p.49 / Chapter 3.6.1 --- The relationship between the system penalty and the ratio fd/fs --- p.49 / Chapter 3.6.2 --- Design of BRL --- p.51 / Chapter 3.6.3 --- Advantages and Disadvantages of the slicing scheme --- p.56 / Chapter 3.7 --- Summary --- p.56 / Chapter Chapter 4 --- Conclusion / Chapter 4.1 --- Fiber recirculating delay loop as a BRL device --- p.58 / Chapter 4.2 --- Slicing scheme --- p.59 / Chapter 4.3 --- Future work --- p.60 / Bibliography --- p.61

Wong, Chi Yan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 134-149). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

by Chun-kit Chan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 143-158). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.