In this book we analyze relaxation oscillations in models of lasers with nonlinear elements controlling light dynamics. The models are based on rate equations taking into account periodic modulation of parameters, optoelectronic delayed feedback, mutual coupling between lasers, intermodal interaction and other factors. With the aim to study relaxation oscillations we present the special asymptotic method of integration for ordinary differential equations and differential-difference equations. As a result, they are reduced to discrete maps. Analyzing the maps we describe analytically such nonlinear phenomena in lasers as multistability of large-amplitude relaxation cycles, bifurcations of cycles, controlled switching of regimes, phase synchronization in an ensemble of coupled systems and others. The book can be fruitful for students and technicians in nonlinear laser dynamics and in differential equations.
A distinctive discussion of the nonlinear dynamical phenomena of semiconductor lasers. The book combines recent results of quantum dot laser modeling with mathematical details and an analytic understanding of nonlinear phenomena in semiconductor lasers and points out possible applications of lasers in cryptography and chaos control. This interdisciplinary approach makes it a unique and powerful source of knowledge for anyone intending to contribute to this field of research. By presenting both experimental and theoretical results, the distinguished authors consider solitary lasers with nano-structured material, as well as integrated devices with complex feedback sections. In so doing, they address such topics as the bifurcation theory of systems with time delay, analysis of chaotic dynamics, and the modeling of quantum transport. They also address chaos-based cryptography as an example of the technical application of highly nonlinear laser systems.
This thesis sheds light on the unique dynamics of optoelectronic devices based on semiconductor quantum-dots. The complex scattering processes involved in filling the optically active quantum-dot states and the presence of charge-carrier nonequilibrium conditions are identified as sources for the distinct dynamical behavior of quantum-dot based devices. Comprehensive theoretical models, which allow for an accurate description of such devices, are presented and applied to recent experimental observations. The low sensitivity of quantum-dot lasers to optical perturbations is directly attributed to their unique charge-carrier dynamics and amplitude-phase-coupling, which is found not to be accurately described by conventional approaches. The potential of quantum-dot semiconductor optical amplifiers for novel applications such as simultaneous multi-state amplification, ultra-wide wavelength conversion, and coherent pulse shaping is investigated. The scattering mechanisms and the unique electronic structure of semiconductor quantum-dots are found to make such devices prime candidates for the implementation of next-generation optoelectronic applications, which could significantly simplify optical telecommunication networks and open up novel high-speed data transmission schemes.
This monograph summarizes major achievements in laser dynamics over the past three decades. The book begins with two introductory Chapters. Chapter 1 offers general considerations on quantum oscillators, formulates the requirements for the laser key elements and shows how these requirements are met in different laser systems. The second Chapter proposes the mathematical models used in semiclassical laser theory, discusses the approximations and simplifications in particular cases, and specifies the range of applicability of these models. In Chapters 3-5 attention is given primarily to the steady states and their stability, the laser behavior in the instability domain, the characteristics of regular and chaotic pulsations and the nature of their mechanisms. Chapter 6 deals with the processes in a laser, accompanying the time variance of laser parameters. Considerable attention is given to a laser response to weak, low-frequency modulation of the parameters. The problems addressed therein are resonant modulation enhancement, transition to the nonlinear regime, chaotic response to periodic impact, spike-like generation due to variation of the cavity geometry and a laser rod temperature drift. Laser behavior is subject to qualitative changes if its optical elements exhibit nonlinear properties. The action of a saturable absorber, which leads to a loss of laser stability and provides passive Q-modulation, is investigated. To a much lesser degree the researchers' attention has been attracted by other nonlinear effects such as self-focusing, e.g., which may have a strong influence on laser dynamics. All of these issues are covered in Chapter 7. The book is intended for researchers, engineers, graduate and post-graduate students majoring in quantum electronics.
Bridging the gap between laser physics and applied mathematics, this book offers a new perspective on laser dynamics. Combining fresh treatments of classic problems with up-to-date research, asymptotic techniques appropriate for nonlinear dynamical systems are shown to offer a powerful alternative to numerical simulations. The combined analytical and experimental description of dynamical instabilities provides a clear derivation of physical formulae and an evaluation of their significance. Starting with the observation of different time scales of an operating laser, the book develops approximation techniques to systematically explore their effects. Laser dynamical regimes are introduced at different levels of complexity, from standard turn-on experiments to stiff, chaotic, spontaneous or driven pulsations. Particular attention is given to quantitative comparisons between experiments and theory. The book broadens the range of analytical tools available to laser physicists and provides applied mathematicians with problems of practical interest, making it invaluable for graduate students and researchers.
This is the first book to be published on physical principles, mathematical models, and practical simulation of GaN-based devices. Gallium nitride and its related compounds enable the fabrication of highly efficient light-emitting diodes and lasers for a broad spectrum of wavelengths, ranging from red through yellow and green to blue and ultraviolet. Since the breakthrough demonstration of blue laser diodes by Shuji Nakamura in 1995, this field has experienced tremendous growth worldwide. Various applications can be seen in our everyday life, from green traffic lights to full-color outdoor displays to high-definition DVD players. In recent years, nitride device modeling and simulation has gained importance and advanced software tools are emerging. Similar developments occurred in the past with other semiconductors such as silicon, where computer simulation is now an integral part of device development and fabrication. This book presents a review of modern device concepts and models, written by leading researchers in the field. It is intended for scientists and device engineers who are interested in employing computer simulation for nitride device design and analysis.
