The objective of this thesis was to evaluate the feasibility of three approaches to thermal imaging that used fiber-optics to decouple the imaging optic from a detector in order to form images without a direct line of sight. All images were formed using 2 m-long fibers, at a working distance of 19 cm, and the ability to detect temperatures between 100 °C to 200 °C. The three approaches were designated active, hybrid, and passive. The active approach involved scanning a single fiber in the image plane to formulate thermal images. Although images had sufficient field of view and spatial resolution, they were not formulated at a frequency of at least 1 Hz using either linear stages or a piezoelectric actuator for scanning. The hybrid approach involved scanning a bundle of fibers in the image plane to formulate a thermal image. Although it was possible to form individual images from fibers within a simple bundle and a seven-fiber bundle with sufficient field of view and spatial resolution, an image formulation frequency of at least 1 Hz was not achieved. While considered feasible, future work is required to identify a suitable motion platform, design a new bundle, and develop a method for stitching images from individual fibers into a single spatially-coherent image in order to achieve an image formulation frequency of at least 1 Hz. Lastly, the passive approach was evaluated in which images were formed using a fixed seven-fiber bundle for direct thermal imaging. The seven-fiber bundle produced images with sufficient field of view and an image formulation frequency on the order of kHz, but without sufficient spatial resolution. Additional work is required to determine the feasibility of designing a passive bundle for a specific spatial resolution, as well as, if overall costs are prohibitive. While no approach satisfied all functional requirements specified herein, evaluation of each approach and a potential solution are provided.

Lasers are an essential technology enabling countless fields of optics, however, their operation wavelengths are limited to isolated regions across the optical spectrum due to the need for suitable gain media. Parametric frequency conversion (PFC) is an attractive means to convert existing lasers to new colors using nonlinear optical interactions rather than the material properties of the host medium, allowing for the development of high power laser sources across the entire optical spectrum. PFC in bulk χ(2) crystals has led to the development of the optical parametric oscillator, which is currently the standard source for high power light at non-traditional wavelengths in the laboratory setting. Ideally, however, one could implement PFC in an optical fiber, thus leveraging the crucial benefits of a guided-wave geometry: alignment-free, compact, and robust operation. Four-wave mixing (FWM) is a nonlinear effect in optical fibers that can be used to convert frequencies, the major challenge being conservation of momentum, or phase matching, between the interacting light waves. Phase matching can be satisfied through the interaction of different spatial modes in a multi-mode fiber, however, previous demonstrations have been limited by mode stability and narrow-band FWM gain. Alternatively, phase matching within the fundamental mode can be realized in high-confinement waveguides (such as photonic crystal fibers), but achieving the anomalous waveguide dispersion necessary for phase matching at pump wavelengths near ∼1 μm (where the highest power fiber lasers emit) comes at the cost of reducing the effective area of the mode, thus limiting power-handling. Here, we specifically consider the class of Bessel-like LP0,m modes in step-index fibers. It has been shown that these modes can be selectively excited and guided stably for long lengths of fiber, and mode stability increases with mode order ‘m’. The effective area of modes in these fibers can be very large (>6000 μm2 demonstrated) and is decoupled from dispersion, allowing for phase matching within a single mode in a power-scalable platform. Furthermore, step-index fibers can guide many different LP0,m modes, allowing access to a highly multi-moded basis set with which to study FWM interactions between different modes. In this thesis we develop techniques to excite, propagate, and characterize LP0,m modes in order to demonstrate FWM in two regimes: monomode interactions comprising waves all belonging to the same mode, and intermodal interactions between different modes. In the monomode regime we demonstrate parametric sources which operate at near-infrared wavelengths under-served by conventional fiber lasers, including 880, 974, 1173, and 1347 nm. The output pulses for these systems are ∼300 ps in duration and reach peak powers of ∼10 kW, representing, to the best our knowledge, the highest peak power fiber laser sources demonstrated at these wavelengths to date. In the intermodal regime, we demonstrate a cascade of FWM processes between different modes that lead to a series of discrete peaks in the visible portion of the spectrum, increasing monotonically in mode order from LP0,7 at 678 nm to LP0,16 at 443 nm. This cascade underscores the huge number of potential FWM interactions between different LP0,m modes available in a highly multi-mode fiber, which scale as N4 for N guided modes. Finally, we demonstrate a novel intermodal FWM process pumped between the LP0,4 and LP0,5 modes of a step-index fiber, which provides broadband FWM gain (63 nm at 1550 nm) while maintaining wavelength separations of nearly an octave (762 nm) – a result that cannot be replicated in the single-mode regime. We seed this process to generate a ∼10 kW, ∼300-ps pulsed fiber laser wavelength-tunable from 786-795 nm; representing a fiber analogue of the ubiquitous Ti:Sapphire laser.

by Poon Wing-chak. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1989. / Includes bibliographies.

by Ka Suen Lee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references. / Chapter Chapter I --- Introduction --- p.1 / Chapter 1.1 --- The evolution of communication networks --- p.1 / Chapter 1.2 --- The development of lightwave communication systems --- p.2 / Chapter 1.3 --- System architecture --- p.9 / Chapter 1.4 --- The motivation of the researches --- p.11 / References --- p.13 / Chapter Chapter II --- Theories --- p.15 / Chapter 2.1 --- The optical time-division multiple-access --- p.15 / Chapter 2.2 --- The operations of 2 x 2 fiber coupler --- p.18 / References --- p.21 / Chapter Chapter III --- Optical loop mirror multiplexer --- p.23 / Chapter 3.1 --- Self Phase Modulation in optical fiber --- p.23 / Chapter 3.2 --- Current developments of the optical loop mirror --- p.24 / Chapter 3.3 --- The principle of the novel time-division multiplexer --- p.30 / Chapter 3.4 --- The experiment and results --- p.31 / Chapter 3.5 --- Analysis on the splitting ratios of the optical loop mirror multiplexer --- p.34 / Chapter 3.6 --- Analysis on the phase of the optical outputs --- p.36 / Chapter 3.7 --- The theories of the optical loop mirror multiplexer --- p.39 / Chapter 3.8 --- The advantages on the optical loop mirror multiplexer --- p.41 / Chapter 3.9 --- The optical bit pattern generation --- p.48 / Chapter 3.10 --- The conclusions of the optical loop mirror multiplexer --- p.49 / References --- p.51 / Chapter Chapter IV --- Optical matrix for high-speed operation in two-dimensional array devices --- p.55 / Chapter 4.1 --- Recent developments in two-dimensional array devices --- p.55 / Chapter 4.2 --- The principle of the novel optical matrix --- p.58 / Chapter 4.3 --- The experiment and results --- p.62 / Chapter 4.4 --- The applications of the novel optical matrix --- p.66 / Chapter 4.5 --- Comparison on the operation modes of the optical matrix --- p.74 / Chapter 4.6 --- Comparison on the construction of the optical matrix --- p.77 / Chapter 4.7 --- The conclusions of the optical matrix --- p.80 / References --- p.81 / Chapter Chapter V --- Conclusions and Future Works --- p.84 / Chapter 5.1 --- The conclusions --- p.84 / Chapter 5.2 --- The future works --- p.86 / Chapter 5.3 --- List of publications --- p.87 / References --- p.88 / Appendix 1 The 1.319 μm Nd:YAG laser system --- p.A-l / Chapter A1.1 --- The laser action of the Neodymium-YAG solid-state laser --- p.A-l / Chapter A1.2 --- The four-level laser system --- p.A-4 / Chapter A1.3 --- The installation and operations of a 1.319μm Nd:YAG laser --- p.A-8 / References --- p.A-21 / Appendix 2 Mode-locking in the Nd:YAG Laser --- p.A-22 / Chapter A2.1 --- The mode-locking technique --- p.A-22 / References --- p.A-26

by Gao Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 62-[65]). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Purpose of Study --- p.5 / Chapter 1.3 --- Organization of Chapters --- p.7 / Chapter 2 --- Overview of Optical Burst-Mode Receivers --- p.8 / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- Burst-Mode Data Transmission --- p.9 / Chapter 2.3 --- Two Main Issues on Burst-Mode Receiver --- p.11 / Chapter 2.4 --- Model of Burst-Mode Receiver --- p.13 / Chapter 2.5 --- Threshold Detection in Burst-Mode Receiver --- p.16 / Chapter 2.6 --- Sensitivity Penalty in Burst-Mode Receiver --- p.20 / Chapter 2.7 --- Chapter Summary --- p.22 / Chapter 3 --- Optimal Detection Threshold in Burst-mode Receiver --- p.24 / Chapter 3.1 --- Introduction --- p.24 / Chapter 3.2 --- Threshold Fluctuation in Burst-Mode Receiver --- p.25 / Chapter 3.3 --- BER of Burst-Mode Receiver --- p.27 / Chapter 3.4 --- Optimal Detection Threshold of Burst-Mode Receivers --- p.31 / Chapter 3.5 --- Simulation Result on the BER of Burst-mode Receiver --- p.36 / Chapter 3.6 --- Chapter Summary --- p.38 / Chapter 4 --- MLT-3 Burst-Mode Receiver --- p.41 / Chapter 4.1 --- Introduction --- p.41 / Chapter 4.2 --- MLT-3 Line Code --- p.42 / Chapter 4.3 --- BER Performance of MLT-3 Continuous-Mode Receiver --- p.45 / Chapter 4.4 --- Burst-mode Receiver For MLT-3 Line Code --- p.49 / Chapter 4.5 --- BER Performance of MLT-3 Burst-Mode Receiver --- p.52 / Chapter 4.6 --- Chapter Summary --- p.55 / Chapter 5 --- Conclusion --- p.59 / Bibliography --- p.62

Production of micro-scale components is an important emergent field. One underdeveloped area is the production of micro-scale 3D surfaces, which has important applications in micro-optics and fibre optic sensors. One particular application is the production of micro-lenses. With scales of less than 200 ??m these lenses can improve light coupling efficiencies in micro-optic systems. However, current lens production techniques have limitations in accuracy and versatility. Creating these surfaces through mechanical micro-grinding has the potential to improve the precision and variety of profiles that can be produced, thus improving transmission efficiencies and leading to new applications. This work presents a novel micro-grinding method for the production of microscale asymmetric, symmetric and axisymmetric curved components from brittle materials such as glasses. A specialised micro-grinding machine and machining system has been designed, constructed and successfully tested and is presented here. This system is capable of producing complex profiles directly on the tips of optical fibre workpieces. A five degree of freedom centring system is presented that can align and rotate these workpieces about a precision axis, enabling axisymmetric grinding. A machine vision system, utilising a microscope lens system and sub-pixel localisation techniques, is used to provide feedback for the process, image processing techniques are presented which are shown to have a sensing resolution of 300 nm. Using these systems, workpieces are centred to within 500 nm. Tools are mounted on nanometre precise motion stages and motion and infeed are controlled. Tooling configurations with flat and tangential grinding surfaces are presented along with control and path generation algorithms. The capabilities and shortcomings of each are presented along with methods to predict appropriate feed rates based on experimental data. Both asymmetric and axisymmetric flat and curved micro-profiles have been produced on the tips of optical fibres using this system. These are presented and analysed and show that the system, as described, is capable of producing high quality micro-scale components with submicron dimensional accuracy and nanometric surface quality. The advantages of this technique are compared with other processes and discussed. Further development of the system and technique are also considered.

Abstract The development of fiber optics industry in Taiwan , comparing with advanced countries is a model of the development of the catching-up economies. The developed countries have already accumulated enough resources and capabilities from the past centuries to build the ability of R&D innovation , processing innovation, and assembly innovation in sequence. The catching-up countries are unable to obtain the same power and financial status as that of the developed countries are primarily due to the less technological advancement. The catching-up economies must initially proceed with the method of reverse engineering. The step initiates with creating the assembly innovation and ends with research pertinent to the utilization of intensive brain-power. The research studies attempts to integrate several related theories and models and form an analytical structure for fiber optics industry in Taiwan. The research studies also discusses the feasibility of fiber optics in Taiwan from both market and technological view , generates several conclusions from the studies , and makes a lot of strategic suggestions for fiber optics industry in Taiwan.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 247-259). Also available on the Internet.

Thesis (M.S.) in Marine Biology--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 62-72).

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 247-259). Also available on the Internet.