Thesis (MSc (Physics))--University of Stellenbosch, 2009. / The exciting field of ultrashort laser optics has experienced tremendous growth since it's inception. One of it's branches that has been of continuous interest is the characterization of ultrashort laser pulses ...

Thesis (MSc (Physics))--University of Stellenbosch, 2008. / Various autocorrelation techniques are employed to characterize ultrashort laser pulses in both the temporal and spectral domain. These techniques are; interference autocorrelation (IAC), modified spectrum autointerferometric correlation (MOSAIC), background-free autocorrelation (BFA) and frequency resolved optical gating (FROG). All of these techniques are based on the interaction of a pulse with a time delayed copy of itself within a Â(2) medium. Experimental setups for BFA and FROG experiments are developed, which exploit the phenomenon of second harmonic generation (SHG). An existing IAC setup is used for temporal pulse characterization. MOSAIC results are obtained through applying a specific Fourier filter to the IAC data. IAC and MOSAIC measurements performed on a commercially available femtosecond laser, indicate that the emitted pulse has a pulse duration less than 150 fs and possesses positive linear chirp. BFA and FROG measurements carried out on the same laser system mirror these results. Pulses emitted by a 20 Hz chirped pulse amplifier are characterized through BFA and FROG. BFA results suggest that the pulse from the amplifier is actually a double pulse. FROG results indicate that the pulse is highly chirped. The experiments and physical interpretations presented in this work demonstrate the preferred methods of optical pulse characterization for ultrashort laser pulses.

Ultralow threshold, compact and highly efficient femtosecond lasers based on Yb³⁺ -doped potassium yttrium tungstate (Yb:KYW) and Yb³⁺ -doped vanadium yttrium oxide (Yb:YVO 4 ) have been demonstrated within this PhD-research project. For a continuous wave unmode-locked Yb:KYW laser a threshold as low as 101 mW was obtained with a slope efficiency of 74 %. By employing a single prism for dispersion control, the laser was tunable between 1012 nm to 1069 nm. When operated in the mode-locked regime, this laser produced transform-limited pulses having durations of 210 fs at a central wavelength of 1044 nm. Stable mode locking was observed for an optimised incident pulse fluence on the SESAM between 140 μJ/cm² to 160 μJ/cm² which was 2-3 times higher than the designed energy pulse fluence of the SESAM (70 μJ/cm² ). The employment of several combinations of chirped mirror designs for control of intracavity group velocity dispersion led to excellent results. The threshold for mode locking was satisfied for a pump power of 255 mW where the slope efficiency was measured to be 62 %. This is the most efficient SESAM-assisted femtosecond laser yet reported and the highest optical-to-optical efficiency of 37 % is exceptional. Transform- limited pulses with durations as short as 90 fs were produced in a spectral region centred on 1052 nm. The success of this research thus represents a good foundation on which to design and build more compact configurations that will incorporate just one chirped mirror for dispersion compensation. A relatively high nonlinear refractive index, n₂ , of 15 x 10⁻¹⁶ cm² /W was measured in Yb:YVO 4 and this affords particular potential for this candidate material in Kerr-lens mode locking. In fact, for operation in the femtosecond domain, the threshold power was 190 mW with a slope efficiency of 26 % and near-transform-limited pulses as short as 61 fs were generated at a centre wavelength of 1050 nm. The main objectives in developing this type of laser relate to a demonstration of high peak power operation in thin disc laser configurations. The deployment of a diode-pumped Yb:KYW femtosecond laser as a pump source for frequency doubling in a periodically-poled LiTaO₃ crystal was realised. The maximum realized output power of 150 mW corresponded to an impressive second harmonic conversion efficiency of 43 %. 225-fs duration green pulses (centred at 525 nm) were generated under the condition of strong focusing in the nonlinear crystal.

Neste trabalho foi investigado o controle do processo de fluorescência excitada por absorção de dois fótons no polímero conjugado MEH-PPV, utilizando um sistema de formatação espectral da fase dos pulsos ultracurtos. Para tal estudo, foi utilizado um oscilador laser de Ti:Safira (15 fs, ~ 800 nm e largura de banda de 60 nm). Através de dois distintos métodos de formatação, observa-se a influência destes no processo de fotodegradação do MEHPPV, inferido pela diminuição da intensidade do sinal de fluorescência. No primeiro método de formatação, é estudada a influência de diferentes chirps impostos aos pulsos no processo de fluorescência do MEH-PPV. Observa-se uma menor taxa de fotodegradação para pulsos com maiores chirps, independente do sinal, em comparação a pulsos no limite de transformada. Esse efeito foi relacionado ao acréscimo na duração temporal dos pulsos com chirp, com consequente diminuição da intensidade. Numa segunda etapa, através do uso de um espelho deformável, a fase espectral do pulso é formatada usando uma máscara de fase senoidal. Neste caso, a intensidade de fluorescência foi modulada em aproximadamente 25%, num claro processo de controle coerente, sem nenhuma diferença apreciável no processo de fotodegradação. Desta forma, técnicas de controle coerente com formatação espectral da fase poderiam ser utilizadas para modular a intensidade do sinal de fluorescência no MEH-PPV, sem detrimento ao processo fotodegradativo. / In this work we studied the control of two-photon excited fluorescence in the conjugated polymer MEH-PPV, using pulse-shaping techniques to manipulate the pulse spectral phase. The experiments were carried out with a Ti:sapphire laser oscillator (15 fs, ~ 800 nm and 60 nm of bandwidth). We investigated the influence of two distinct pulse-shaping methods in the MEH-PPV photodegradation, inferred by the decrease in the fluorescence intensity. In the first method, we studied the effect of different pulse chirps on the MEH-PPV fluorescence. A smaller photodegradation rate was observed for pulses with higher chirps, independently of its sing, in comparison with pulses close to the Fourier Transform limit. This effect was attributed to the increase in the pulse duration for chirped pulses, and consequent decrease in the pulse intensity. In a second stage, we modulate the pulse spectral phase by employing a senoidal phase mask though a deformable mirror. In this case, a 25% modulation in the fluorescence intensity was determined, whereas no considerable effect was observed in the photodegradation. In this way, coherent control techniques employing spectral phase pulse-shaping could be used to modulate MEH-PPV fluorescence, without any negative effect to its photodegradation.

Laser techniques, such as gain / Q switching, mode-locking, have successfully overcome the energy restriction of gain clamping in the stead-state operated lasers, and allowed the generation of giant pulses with short pulse durations. However, gain saturation further limits the amount of stored energy in a gain medium, and therefore limits the possible maximum pulse energy obtained by laser techniques. Here we circumvent both gain clamping and the capacity limitation of energy storage by operating the double-quantum-well laser diode chips on ultrafast gain-switching model using femtosecond (fs) laser pulses as the optical pump. The advantage of our pumping approach is that the fs pulse can instantly produce a very large number of carriers, and therefore enable the formation of non-equilibrium coherent e-h BCS-like condensate state in a large energy region from the lowest QW subband edges to the highest subband and then obtain the ultra-broadband superrandiant pulses. / Superradiance (SR) or the coherent spontaneous emission is not a new quantum optics phenomenon, which has been proposed in 1954 by R. Dicke, even earlier than the invention of laser. It is famous as by its ultrashort duration, high peak power, high coherence and high timing jitter. Recently, femtosecond SR pulses have been generated from semiconductors. This investigation has revived both theoretical and experimental studies of SR emission. / In this thesis, we have demonstrated the generation of intense, delayed SR pulses from the InP based double quantum well laser diode at room temperature. The 1040 nm femtosecond laser was applied as the optical pumping source, and when the pump power is high enough, the cooperative recombination of e-h pairs from higher order quantum energy levels can occur to generate SR bursts earlier than the cooperative emission from the lower quantum energy levels. Then, ultra-broadband TM polarized SR pulses have been firstly generated at room temperature. Our experiments also provide a well prospect of ultra-high energy light pulse generation based on SR, besides, the ultra-broadband spectrum is promising for applications in a diverse range of fields, including optical coherent tomography and spectroscopy. / Graphene, a truly 2D material, has stimulated a vast amount of research in recent years. In our work, we have wet transferred the CVD grown monolayer graphene onto the top of our LD chips. With the combination of graphene on top of QW LD, the evanescent field of TM polarized modes can well interact with top graphene layer, and therefore, produce a dramatically modulation of the output power, and optical spectra of output pulses. The graphene-on-DQW LD will be promising to explore the novel devices, such as optical modulator, which will greatly promote the applications of SR emission in near future. / 激光技術，諸如增益 / Q調製，鎖模，已經成功克服了穩態激光器存在的增益箝制現象，從而產生了脈寬窄，峰值功率高的巨脈衝。然而，增益飽和現象又進一步限制了增益介質的儲能上限，因而設定了激光技術產生的脈衝的能量上限。在這裡，我們以飛秒激光為光泵,使量子阱激光器工作在超快增益調製模式, 從而有效地規避了增益箝制和儲能限制。这种泵浦方式的优势在于可以瞬间产生极大量的载流子，從而可以在一个很宽的能带区间内（从量子阱的最低能级到最高能级）形成非平衡相干类BCS状态的电子空穴对的凝聚态，从而产生宽频超辐射。 / 超輻射（SR），或稱為相干的自發輻射並非是一個新的量子光學現象，早在1954年就被由R. Dicke提出了，比發明激光器還早。SR以它脈衝時間短，峰值功率高，相干性好，以及脈衝定時抖動高等特點而聞名。近來，不同的研究組報導了他們用半導體材料產生了SR, 復興了理論和實驗雙方面對SR的研究。 / 在這篇論文中，我們論證了如何用飛秒激光泵浦雙量子阱激光二極管產生高功率帶有延時的超辐射脈衝。當泵功率足夠高時，高量子能級的電子空穴對先於低能級的電子空穴對發生超輻射，從而第一次在室溫下得到了超寬頻譜的超輻射脈衝。此外，我們證明了超輻射光是TM偏振的。根據我們的結果可以預測關於SR的超高能量脈衝的研究以及相关应用具有光明的發展前景，比如，SR可用於包括光學相干斷層成像和光譜學等的各種各樣的先進領域。 / 石墨烯，真正的2D材料，近年來激發了巨大的研究熱潮。我們用濕法轉移的方法將化學氣相沉積生長的單層石墨烯鋪到我們的樣品表面。這使TM偏振模式的漸逝場能很好地與石墨烯層作用，因此，顯著調製SR脈衝的功率和頻譜。石墨烯與多量子阱激光二極管的結合將大大推動了新型器件的研究，如光調製器等，這將大大改善SR的應用前景。 / Liu, Jingjing. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2015. / Includes bibliographical references. / Abstracts also in Chinese. / Title from PDF title page (viewed on 21, December, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

by Kwok Chi Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references. / Abstract / Acknowledgements / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Basic Concepts of Lasers and Simple Survey of Laser Theories --- p.4 / Chapter 2.1 --- Introduction --- p.4 / Chapter 2.1.1 --- Basic Structure of a Laser --- p.4 / Chapter 2.1.2 --- "Concepts of "" Mode"" arid "" Mode-Locking""" --- p.6 / Chapter 2.2 --- Brief Review of Laser Theories --- p.9 / Chapter 2.3 --- Other Simple Models --- p.12 / Chapter 2.4 --- Review of the Maxwell-Bloch Equations --- p.17 / Chapter 2.4.1 --- Derivation of Maxwell-Bloch Equations --- p.17 / Chapter 2.4.2 --- Continuous-Wave Operation --- p.23 / Chapter 2.4.3 --- Mean-Field Approximation and Lorenz-Haken Instability --- p.24 / Chapter 2.4.4 --- Adiabatic Elimination of Fast Variables --- p.26 / Chapter 2.4.5 --- Thin-Sheet-Gain Approximation for Multimode Lasers --- p.30 / Chapter 2.4.6 --- Self-Mode-Locking Predicted by Using Maxwell-Bloch Equations --- p.33 / Chapter 2.4.7 --- Hysteresis Phenomena in Switching the Cavity Detuning --- p.35 / Chapter 3. --- "Moving-Mirror ""Mode-Locking""" --- p.41 / Chapter 3.1 --- Conventional Laser Mode-Locking --- p.41 / Chapter 3.1.1 --- Preliminaries： What is Mode-Locking (Conventional) ？ --- p.41 / Chapter 3.1.2 --- Active Mode-Locking and Passive Mode-Locking --- p.43 / Chapter 3.1.3 --- Spectra of Conventional Mode-Locked Lasers --- p.49 / Chapter 3.2 --- Moving-Mirror Mode-Locking --- p.50 / Chapter 3.2.1 --- Historical Notes --- p.50 / Chapter 3.2.2 --- Previously Proposed Explanations --- p.54 / Chapter 3.3 --- MMML Mechanism: our Proposal --- p.59 / Chapter 3.3.1 --- Relation between MMML Lasers and FSFC Lasers --- p.60 / Chapter 3.3.2 --- Concept of Moving Modes --- p.62 / Chapter 3.3.3 --- How are the Moving Modes Locked ？ --- p.64 / Chapter 3.4 --- Numerical Simulations ´ؤ Method and Results --- p.68 / Chapter 3.4.1 --- Description of Our Numerical Model --- p.68 / Chapter 3.4.2 --- Tests on the Simulation Method --- p.71 / Chapter 3.4.3 --- Ultrashort Pulses Generation of a MMML Laser --- p.73 / Chapter 3.4.4 --- Modulation of the Pulses --- p.74 / Chapter 3.4.5 --- Broadband or Discrete Spectra ？ --- p.75 / Chapter 3.4.6 --- Different Operation Regimes in MMML Lasers --- p.79 / Chapter 3.4.7 --- Why Period-T/2 Pulses --- p.84 / Chapter 3.4.8 --- Auto-Correlation Function of the Electric Field --- p.86 / Chapter 3.4.9 --- FSFC Laser with Injection Signal --- p.87 / Chapter 3.4.10 --- MMML in Class C Laser: d = 1.0 --- p.88 / Chapter 3.4.11 --- Exciting the Relaxation Oscillation Resonance --- p.89 / Chapter 4. --- Discussion and Conclusion --- p.92 / Chapter 4.1 --- Limitation of (Conventional) Thin-Sheet-Gain Approximation --- p.92 / Chapter 4.1.1 --- Problem with the Conventional Thin -Sheet-Gain Approximation --- p.92 / Chapter 4.1.2 --- Modified Thin-Sheet-Gain Approximation --- p.93 / Chapter 4.2 --- Concluding Remarks; Possibilities of Further Research --- p.97 / References and Notes / Appendix: Source Codes of the Fortran Program

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 Sui-Pan Yam. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references. / Abstract also in Chinese. / Acknowledgements --- p.V / Abstract --- p.VI / Chapter Chapter 1 --- Introduction --- p.1-1 / Chapter 1.1) --- Tunable Multi-Wavelength Optical Sources --- p.1 -1 / Chapter 1.2) --- All-Optical Switching --- p.1 -3 / Chapter 1.2.1) --- Nonlinear Effect / Chapter 1.2.2) --- Special Design of the Laser Structure / Chapter 1.2.3) --- Self-Injection Seeding of Fabry-Perot Laser Diode / Chapter 1.3) --- About This Project --- p.1-6 / Chapter Chapter 2 --- Basic Theory --- p.2-1 / Chapter 2.1) --- Mechanism of Gain-Switching --- p.2-1 / Chapter 2.1.1) --- General Description / Chapter 2.1.2) --- "Optical Pulsewidth, Spectra, and Frequency Chirping of Gain-Switched Pulses" / Chapter 2.2) --- Mechanism of Self-Injection Seeding --- p.2-8 / Chapter 2.2.1) --- General Description / Chapter 2.2.2) --- Dynamics of Single-Mode Formation / Chapter 2.2.3) --- Frequency Evolution of the Laser Diode for Cavity Mode Selection / Chapter 2.2.4) --- Turn-On Delay Time Jitter (TOJ) / Chapter 2.3) --- Mechanism of Injection Seeding --- p.2-17 / Chapter 2.3.1) --- General Description / Chapter 2.3.2) --- The Model of Weak Injection / Chapter 2.3.3) --- The Model of Strong Injection / Chapter Chapter 3 --- Single- and Multi-wavelength Optical Pulses Generated by a Diffraction Grating --- p.3-1 / Chapter 3.1) --- Introduction --- p.3-1 / Chapter 3.2) --- Basic Principle --- p.3-2 / Chapter 3.3) --- Experimental Setup --- p.3-5 / Chapter 3.4) --- Results and Discussion --- p.3-7 / Chapter 3.4.1) --- Spectral Characteristics Analysis / Chapter 3.4.2) --- Individually Access of the Four-Wavelength Output / Chapter 3.4.3) --- The Optical Pulsewidth Characteristics / Chapter 3.4.4) --- Discussion / Chapter 3.5) --- Summary --- p.3-14 / Chapter Chapter 4 --- Using a Highly Dispersive Fiber for Tunable Multi-Wavelength Pulse Generation --- p.4-1 / Chapter 4.1) --- Introduction --- p.4-1 / Chapter 4.2) --- Basic Principle --- p.4-2 / Chapter 4.3) --- Experimental Setup --- p.4-5 / Chapter 4.4) --- Experimental Results --- p.4-7 / Chapter 4.4.1) --- Spectral and Temporal Characteristics / Chapter 4.4.2) --- Wavelength Tuning / Chapter 4.4.3) --- Individually Access of Two Wavelength Channels / Chapter 4.4.4) --- Multi-Wavelength Generation / Chapter 4.5) --- Summary --- p.4-13 / Chapter Chapter 5 --- Comparison of Two Self-Seeding Configurations --- p.5-1 / Chapter 5.1) --- Introduction --- p.5-1 / Chapter 5.2) --- Polarization Sensitivity --- p.5-1 / Chapter 5.3) --- Stability --- p.5-2 / Chapter 5.4) --- Tunability --- p.5-2 / Chapter 5.5) --- Simplification --- p.5-3 / Chapter 5.6) --- Summary of the advantages and disadvantages of Two Configurations --- p.5-4 / Chapter Chapter 6 --- All-Optical Wavelength Switching achieved by Self-Seeding and External Injection-Seeding --- p.6-1 / Chapter 6.1) --- Introduction --- p.6-1 / Chapter 6.2) --- Experimental Setup --- p.6-2 / Chapter 6.3) --- Results and Discussion --- p.6-4 / Chapter 6.3.1) --- Spectral Characteristics / Chapter 6.3.2) --- The Optical Pulsewidth / Chapter 6.3.3) --- The Optical Switching Behaviors / Chapter 6.3.4) --- The Detail Information of Switching / Chapter 6.3.5) --- Optical Power / Chapter 6.4) --- Summary --- p.6-10 / Chapter Chapter 7 --- A Novel Self-Injection Seeding Scheme --- p.7-1 / Chapter 7.1) --- Introduction --- p.7-1 / Chapter 7.2) --- Basic Principle --- p.7-2 / Chapter 7.3) --- Experimental Setup --- p.7-9 / Chapter 7.4) --- Results and Discussion --- p.7-11 / Chapter 7.4.1) --- Spectral and Temporal Characterizations of Two-Wavelength Switching / Chapter 7.4.2) --- Different Wavelength Selection / Chapter 7.4.3) --- Operation Frequency Against the Fiber Length / Chapter 7.4.4) --- Multi-Wavelength Generation / Chapter 7.5) --- Discussion --- p.7-20 / Chapter 7.6) --- Summary --- p.7-22 / Chapter Chapter 8 --- Comparison of Switching Methods --- p.8-1 / Chapter 8.1) --- Introduction --- p.8-1 / Chapter 8.2) --- Switching between Self-Seeding and Injection-Seeding --- p.8-1 / Chapter 8.3) --- Switching by Self-Seeding of a F-P Laser Diode --- p.8-2 / Chapter 8.4) --- Summary --- p.8-3 / Chapter Chapter 9 --- Conclusion --- p.9-1 / References / Figure Captions / Appendix 一 Equipment Descriptions / List of Accepted and Submitted Publications

Chan Sze-wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.vi / Table of contents --- p.vii / List of figure --- p.xi / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Optical non-linearity of fiber and semiconductor optical amplifier (SOA) --- p.2 / Chapter 1.2. --- Applications on optical non-linearity --- p.3 / Chapter 1.2.1. --- Wavelength tunable pulse generation --- p.3 / Chapter 1.2.2. --- Wavelength conversion --- p.5 / Chapter 1.2.3. --- All-optical NRZ to RZ format conversion --- p.7 / Chapter 1.2.4. --- All-optical pulse compression and reshaping --- p.9 / Chapter 1.3. --- Overview --- p.11 / Reference --- p.13 / Chapter 2. --- Principles and Theories --- p.16 / Chapter 2.1. --- Optical non-linearity --- p.17 / Chapter 2.1.1. --- Self-phase modulation (SPM) --- p.19 / Chapter 2.1.2. --- Cross-phase modulation (XPM) --- p.22 / Chapter 2.2. --- Principle of dispersion tuning --- p.25 / Chapter 2.2.1. --- Nonlinear optical loop mirror (NOLM) incorporated with SOA --- p.29 / Chapter 2.2.2. --- Principle of compensated dispersion tuning in harmonically mode-locked fiber ring --- p.33 / Chapter 2.3 --- Principle of double-pass dispersion-shifted fiber (DSF) based on SPM --- p.36 / Reference --- p.38 / Chapter 3. --- Preliminary experimental studies on spectral broadeningin SOAs and DSF by XPM --- p.39 / Chapter 3.1. --- XPM in SOA --- p.40 / Chapter 3.2. --- XPM in DSF --- p.44 / Chapter 3.3. --- Comparison in XPM performance between SOA and DSF --- p.47 / Chapter 4. --- Harmonically mode-locked fiber laser with an optically selectable wavelength --- p.48 / Chapter 4.1. --- Introduction to wavelength tunable pulse generation and basic idea --- p.49 / Chapter 4.2. --- Experimental details --- p.51 / Chapter 4.3. --- Results and discussions --- p.55 / Chapter 4.4. --- Conclusion --- p.61 / Reference --- p.62 / Chapter 5. --- Spectral broadening by XPM in DSF for wavelength conversion --- p.64 / Chapter 5.1. --- Overview of wavelength conversion --- p.65 / Chapter 5.2. --- Description of experimental setup --- p.67 / Chapter 5.3. --- Optical spectral analysis and eye patterns --- p.69 / Chapter 5.4. --- Data Analysis --- p.72 / Chapter 5.5. --- Conclusion --- p.75 / Reference --- p.76 / Chapter 6. --- Spectral filtering from a cross-phase modulated signal for all- optical NRZ to RZ format conversion --- p.77 / Chapter 6.1. --- Importance of format conversion --- p.78 / Chapter 6.2. --- Principle and explanation of experimental setup --- p.79 / Chapter 6.3. --- Experimental results and bit error rate test --- p.81 / Chapter 6.4. --- Conclusion --- p.87 / Reference --- p.88 / Chapter 7. --- Spectral filtering from a cross-phase modulated signal for all- optical pulse compression and reshaping in a DSF --- p.90 / Chapter 7.1. --- Pulse compression by XPM / Chapter 7.1.1. --- Introduction --- p.91 / Chapter 7.1.2. --- Details of experimental setup --- p.93 / Chapter 7.1.3. --- Experimental results / Chapter 7.1.3.1. --- Output spectra and eye patterns --- p.95 / Chapter 7.1.3.2. --- Data analysis and discussions --- p.97 / Chapter 7.2. --- Pulse restoration by XPM / Chapter 7.2.1. --- Details of experiment --- p.99 / Chapter 7.2.2. --- Output eye patterns --- p.101 / Chapter 7.3. --- Conclusion for pulse compression and reshaping by XPM --- p.102 / Reference --- p.103 / Chapter 8. --- Spectral filtering from a self-phase modulated signal with double-pass DSF for all-optical pulse compression and reshaping --- p.104 / Chapter 8.1. --- Introduction to pulse compression by SPM and basic idea of double-pass DSF --- p.105 / Chapter 8.2. --- Schematic diagram of experimental setup --- p.107 / Chapter 8.3. --- Experimental Results and discussions / Chapter 8.3.1. --- Results measured by optical spectrum analyzer and oscilloscope --- p.109 / Chapter 8.3.2. --- Data comparison with conventional SPM and bit-error rate test --- p.113 / Chapter 8.4. --- Conclusion --- p.117 / Reference --- p.118 / Chapter 9. --- Conclusion and future works / Chapter 9.1. --- Conclusion --- p.119 / Chapter 9.2. --- Possible future works --- p.122 / Appendix / List of publications --- p.A-l