Surface waves exist along the interfaces between two different media and are known to display properties that have no analogue in continuous systems. In years past, they have been the subject of many studies in a diverse collection of scientific disciplines. In optics, one of the mechanisms through which optical surface waves can exist is material nonlinearity. Until recently, most of the activity in this area was focused on interfaces between continuous media but no successful experiments have been reported. However, the growing interest that nonlinear discrete optics has attracted in the last two decades has raised the question of whether nonlinear surface waves can exist in discrete optical systems. In this work, a detailed experimental study of linear and nonlinear optical wave propagation at the interface between a discrete one-dimensional Kerr-nonlinear system and a continuous medium (slab waveguide) as well as at the interface between two dissimilar waveguide lattices is presented. The major part of this dissertation is devoted to the first experimental observation of discrete surface solitons in AlGaAs Kerr-nonlinear arrays of weakly coupled waveguides. These nonlinear surface waves are found to localize in the channels at and near the boundary of the waveguide array. The key unique property of discrete surface solitons, namely the existence of a power threshold, is investigated in detail. The second part of this work deals with the linear light propagation properties at the interface between two dissimilar waveguide arrays (so-called waveguide array hetero-junction). The possibility of three different types of linear interface modes is theoretically predicted and the existence of one of them, namely the staggered/staggered mode, is confirmed experimentally. The last part of the dissertation is dedicated to the investigation of the nonlinear properties of AlGaAs waveguide array hetero-junctions. The predicted three different types of discrete hybrid surface solitons are analyzed theoretically. The experimental results on observation of in-phase/in-phase hybrid surface solitons localized at channels on either side of the interface are presented and different nature of their formation is discussed.

Esta tesis constituye un estudio detallado y exhaustivo de las propiedades de una variedad específica de ondas ópticas solitarias. Observadas experimentalmente por primera vez en 1995, estas ondas estan formadas por un haz óptico a frecuencia fundamental y su segundo armónico que están ligados entre sí y viajan juntos en el material cuadrático; y son debidas al equilibrio entre la difracción lineal que sufre el haz al propagarse y un término no lineal de segundo orden en la susceptibilidad del medio. Las llamamos por eso solitones ópticos en medios cuadráticos o simplemente 'solitones cuadráticos'. También se les conoce como 'Solitones Multicolor' aludiendo al hecho de que requieren de haces a diferentes frecuencias para formarse.Un medio no-lineal cuadrático tiene por fuerza que ser no-centrosimétrico, lo cual es una variedad de anisotropía. Una gran parte de los materiales no-lineales cuadráticos (los que tienen mayor interés para la industria) son uniaxiales lo que significa que presentan un eje de simetría que suele llamarse eje óptico. De la dirección de un haz relativa a ese eje óptico dependen las características de la propagación del haz en el medio cuadrático no-lineal. Una consecuencia de eso en configuraciones de interés es un desvío ('walk-off') sufrido por el haz respecto a su dirección de propagación inicial al entrar en el material no-lineal.Las propiedades de los solitones cuadráticos 'caminantes' son también estudiadas en la tesis, estableciendo que existe una relación entre la potencia inyectada en el medio y el ángulo de desvío (walking angle).Una parte importante de la tesis está dedicada al estudio a través de exhaustivos experimentos numéricos del potencial de estas ondas solitarias para constituir la base de dispositivos de conmutación y encaminamiento totalmente ópticos que puedan hacer realidad la promesa de la red transparente totalmente óptica. Los experimentos han permitido identificar varias configuraciones de interés con niveles de potencia y dimensiones que permiten plantearse el diseño y construcción de dispositivos comerciales de conmutación y encaminamiento totalmente ópticos basados en solitones ópticos cuadráticos. / This thesis is a comprehensive study of the fundamental properties of a specific kind of optical spatial solitary waves. First observed experimentally in 1995, these solitary waves are formed by an optical beam at a fundamental frequency and its second harmonic which propagate together and are mutually entangled; and are due to a balanced interplay between the beams' linear diffraction and a second-order nonlinear susceptibility of the medium. They are thereby referred as 'Optical Solitons in Quadratic Nonlinear Media' or simply 'Quadratic Solitons', They are also known as 'Multicolor Solitons' recalling that they are formed by beams at different frequencies.A quadratic nonlinear media needs to be non centrosymmetric which is a special kind of anisotropy. A great deal of quadratic nonlinear materials (the most used by industry such as lithim niobate, KTP, etc.) are uniaxial meaning that they feature a symmetry axis known as 'optical axis'. The direction of propagation of an optical beam relative to that axis determines the characteristics of the beam's propagation through the quadratic nonlinear material. A main result of that in some configurations of interest is a walk-off suffered by the beam as it enters the quadratic material.The properties of the families of quadratic solitons in the presence of a linear walk-off (quadratic walking solitons) are studied as well in the thesis stating that there is a relationship between the power injected into the medium and the walking angle, suitable to applications of all-optical switching and routing.An important last part of the thesis is devoted to the study from a practical viewpoint and through extensive numerical experiments of the potential of these solitary waves as the basis of practical all-optical switches and routers which could take the all-optical transparent network to a reality. The experiments have allowed to identify several configurations of interest with power level and dimensions suited to practical applications which could allow the production of commercial all-optical switching and routing devices based on quadratic solitons.

published_or_final_version / Physics / Doctoral / Doctor of Philosophy

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by Cheong Lik-ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references. / Abstract / Acknowledgments / Chapter Chapter I --- Introduction --- p.1 / Chapter 1.1 --- Definitions of Optical Solitons --- p.1 / Chapter 1.2 --- A Brief History of Optical Solitons --- p.2 / Chapter 1.3 --- Generation of Optical Solitons --- p.4 / Chapter 1.4 --- About the Thesis --- p.6 / References --- p.8 / Chapter Chapter II --- General Theory of Optical Solitons --- p.10 / Chapter 2.1 --- Propagation Equation of Optical Solitons --- p.10 / Chapter 2.2 --- Solving of the NLSE --- p.16 / Chapter 2.2.1 --- Inverse Scattering Transform --- p.17 / Chapter 2.2.2 --- Split-Step Fourier Method --- p.20 / Chapter 2.3 --- Fundamental Solitons --- p.22 / Chapter 2.4 --- Higher Order Solitons --- p.25 / References --- p.27 / Chapter Chapter III --- Modeling of Soliton Generation Systems Part I: Gain Switching and Spectral Windowing --- p.29 / Chapter 3.1 --- General Descriptions --- p.29 / Chapter 3.2 --- About the Gain Switching and Spectral Windowing Method --- p.30 / Chapter 3.3 --- Gain Switching of Semiconductor Laser Diodes --- p.30 / Chapter 3.3.1 --- Rate Equations of Semiconductor Laser Diodes --- p.31 / Chapter 3.3.2 --- Analysis of Gain Switching Pulses --- p.35 / Chapter 3.3.3 --- Propagation of Gain Switching Pulses in Optical Fibers --- p.42 / Chapter 3.4 --- Spectral Windowing --- p.47 / Chapter 3.5 --- Erbium-Doped Fiber Amplifier --- p.50 / Chapter 3.5.1 --- Theoretical Model of Erbium-Doped Fiber Amplifier --- p.51 / Chapter 3.5.2 --- Pulse Evolutions in Erbium-Doped Fiber Amplifier --- p.54 / Chapter 3.5.3 --- Analysis of Amplification for Gain Switching Pulses --- p.55 / Chapter 3.6 --- Optimal Condition for the Gain Switching and Spectral Windowing Method --- p.60 / References --- p.61 / Chapter Chapter IV --- Modeling of Soliton Generation Systems Part II: Fiber Ring Laser --- p.64 / Chapter 4.1 --- General Descriptions --- p.64 / Chapter 4.2 --- About the Fiber Ring Laser Method --- p.65 / Chapter 4.3 --- Principles of the Fiber Ring Laser --- p.66 / Chapter 4.4 --- Mathematical Model of the Fiber Ring Laser --- p.67 / Chapter 4.4.1 --- Cross Phase Modulation --- p.68 / Chapter 4.4.2 --- Evolution Equations in Ordinary Optical Fibers --- p.70 / Chapter 4.4.3 --- Evolution Equations in Erbium-Doped Fibers --- p.71 / Chapter 4.4.4 --- Description of Polarization Controllers --- p.72 / Chapter 4.5 --- Analysis of Optical Pulses Generated from Fiber Ring Lasers --- p.74 / Chapter 4.5.1 --- Properties of the Mode Locking Process --- p.74 / Chapter 4.5.2 --- Pulse Width Analysis --- p.79 / Chapter 4.5.3 --- Constant Pulse Width Analysis --- p.88 / Chapter 4.5.4 --- Self-Starting Process --- p.91 / Chapter 4.6 --- Stimulated Raman Scattering in Fiber Ring Lasers --- p.94 / Chapter 4.6.1 --- Mathematical Descriptions of Stimulated Raman Scattering --- p.95 / Chapter 4.6.2 --- Effects of Stimulated Raman Scattering on Fiber Ring Lasers --- p.98 / Chapter 4.7 --- Comparison of the Two Methods --- p.100 / References --- p.102 / Chapter Chapter V --- Experimental Investigation of Fiber Ring Lasers --- p.105 / Chapter 5.1 --- Experimental Setup --- p.105 / Chapter 5.2 --- Experimental Results --- p.106 / Chapter 5.3 --- Discussions --- p.117 / References --- p.122 / Chapter Chapter VI --- Conclusion --- p.123 / Chapter Chapter VII --- Future Extensions --- p.127 / Appendix I Solving the NLSE by the Inverse Scattering Transform --- p.A1 / Appendix II Solving the NLSE by the Split-Step Fourier Method --- p.A9 / Appendix III Parameter Listing --- p.A12

Chan Tak Shun = 摻鐵鈮酸鋰晶體中相位相關的亮光生伏打空間孤子的相互作用的觀察及光生伏打媒介中高調制深度下所寫的光折變全息圖的理論研究 / 陳德信. / Thesis submitted in: July 2006. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 115-116). / Abstracts in English and Chinese. / Chan Tak Shun = Shan tie ni suan li jing ti zhong xiang wei xiang guan de liang guang sheng fu da kong jian gu zi de xiang hu zuo yong de guan cha ji guang sheng fu da mei jie zhong gao diao zhi shen du xia suo xie de guang zhe bian quan xi tu de li lun yan jiu / Chen Dexin. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.v / Chapter Chapter 1 --- Introduction --- p.1 / References --- p.9 / Chapter Chapter 2 --- Background --- p.10 / Chapter 2.1 --- Space-Charge Field and Band Transport Model --- p.10 / Chapter 2.2 --- Photorefractive Effect and Nonlinear Wave Equation --- p.24 / Chapter 2.3 --- Two-Wave Mixing and Diffraction of Light Incident onto an Index Grating --- p.34 / Chapter 2.4 --- Photorefractive Spatial Solitons --- p.48 / References --- p.60 / Chapter Chapter 3 --- Relevance of interpretation of experimental results of interactions of optical spatial solitons and interaction geometry --- p.62 / Chapter 3.1 --- Introduction --- p.62 / Chapter 3.2 --- Theoretical Model --- p.63 / Chapter 3.3 --- Results and Discussion --- p.65 / Chapter 3.4 --- Conclusions --- p.71 / References --- p.72 / Chapter Chapter 4 --- Experimental investigation of phase-dependent interactions of photovoltaic bright spatial solitons in photorefractive Fe:LiNb03 --- p.75 / Chapter 4.1 --- Introduction --- p.75 / Chapter 4.2 --- Theoretical Background --- p.76 / Chapter 4.3 --- Experiment --- p.83 / Chapter 4.4 --- Results and Discussion --- p.86 / Chapter 4.5 --- Conclusions --- p.90 / References --- p.91 / Chapter Chapter 5 --- Photorefractive hologram writing with high modulation depth in photovoltaic media under different boundary conditions --- p.94 / Chapter 5.1 --- Introduction --- p.94 / Chapter 5.2 --- Theoretical Model and Method --- p.97 / Chapter 5.3 --- Results and Discussion --- p.99 / Chapter 5.4 --- Conclusions --- p.114 / References --- p.115 / Chapter Chapter 6 --- Conclusions and future outlook --- p.117

by Li Kam Shun. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 76). / 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.

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 66-71).