Single Frequency Semiconductor Lasers

This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

This tutorial text describes the properties of advanced semiconductor lasers in detail. Although the text gives a detailed theoretical account, a number of practical examples and experimental results are described as well. The material presented is at an advanced level and is of particular interest to scientists and engineers with a basic familiarity with semiconductor lasers who would like a description of the properties of single frequency semiconductor lasers and of the possibilities offered by these devices.

Single frequency semiconductor lasers are of interest for communication systems and spectroscopy. In communications, narrow linewidth is desirable to minimize dispersion effects and low cross-talk multiple wavelength channels on a single fiber. For GaAs-based lasers, the interest in narrow linewidth sources comes from the spectroscopy community that desires a light source that can be tuned to very narrow absorption spectra of various materials. For both of these applications, narrow linewidth, wavelength tunable semiconductor lasers are well-suited. This thesis describes the development of a single epitaxial growth ridge waveguide distributed Bragg reflector (RW-DBR) laser. These lasers exhibit low thresholds, fairly high slope efficiencies, and single frequency operation with very narrow linewidth. The fabrication requires only a single epitaxial growth of a standard laser structure and then an anisotropic etch to transfer a grating pattern from the top surface of the laser into the epitaxial layers. The initial RW-DBR lasers fabricated by this method had symmetric cladding layers with a thickness of 1.2 $mu$m, which required etch depths of over 1 $mu$m in order to couple adequately to the optical mode. This required a highly anisotropic etch and limited the device design to third-order gratings. However, fairly good device performance was demonstrated with these symmetric cladding RW-DBR lasers. To relax the constraints on the grating etch, an asymmetric cladding separate confinement heterostructure (AC-SCH) laser was developed. The AC-SCH design reduces the thickness of the top cladding layer, which results in shallower depths for the grating etch and allows the fabrication of more efficient second-order DBR gratings. The incorporation of the AC-SCH into the RW-DBR laser reduces the threshold current, increases the efficiency, and decreases the spectral linewidth.

Applications of semiconductor lasers with optical feedback systems are driving rapid developments in theoretical and experimental research. The very broad wavelength-gain-bandwidth of semiconductor lasers combined with frequency-filtered, strong optical feedback create the tunable, single frequency laser systems utilised in telecommunications, environmental sensing, measurement and control. Those with weak to moderate optical feedback lead to the chaotic semiconductor lasers of private communication. This resource illustrates the diversity of dynamic laser states and the technological applications thereof, presenting a timely synthesis of current findings, and providing the roadmap for exploiting their future potential. * Provides theory-based explanations underpinned by a vast range of experimental studies on optical feedback, including conventional, phase conjugate and frequency- filtered feedback in standard, commercial and single-stripe semiconductor lasers * Includes the classic Lang-Kobayashi equation model, through to more recent theory, with new developments in techniques for solving delay differential equations and bifurcation analysis * Explores developments in self-mixing interferometry to produce sub-nanometre sensitivity in path-length measurements * Reviews tunable single frequency semiconductor lasers and systems and their diverse range of applications in sensing and optical communications * Emphasises the importance of synchronised chaotic semiconductor lasers using optical feedback and private communications systems Unlocking Dynamical Diversity illustrates all theory using real world examples gleaned from international cutting-edge research. Such an approach appeals to industry professionals working in semiconductor lasers, laser physics and laser applications and is essential reading for researchers and postgraduates in these fields.

This updated, second edition textbook provides a thorough and accessible treatment of semiconductor lasers from a design and engineering perspective. It includes both the physics of devices as well as the engineering, designing and testing of practical lasers. The material is presented clearly with many examples provided. Readers of the book will come to understand the finer aspects of the theory, design, fabrication and test of these devices and have an excellent background for further study of optoelectronics.

Market: Graduate students and researchers requiring an up-to-date review of current work in semiconductor lasers. "There's plenty to surprise and impress anyone who hasn't been following the semiconductor laser field intently." New Scientist This book fills a major gap in the literature of semiconductor lasers by providing, in a single volume, ten up-to-date review articles written in a pedagogical manner by well-known experts. The topics cover the entire range of current activity in the field. The last two chapters of the book are devoted to applications and are intended to provide a perspective on how the research advances described in earlier chapters eventually translate into commercial products.

This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in semiconductor lasers are discussed, but also for example the method of self-mixing interferometry in quantum-cascade lasers, which is indispensable in practical applications. Further, this edition covers chaos synchronization between two lasers and the application to secure optical communications. Another new topic is the consistency and synchronization property of many coupled semiconductor lasers in connection with the analogy of the dynamics between synaptic neurons and chaotic semiconductor lasers, which are compatible nonlinear dynamic elements. In particular, zero-lag synchronization between distant neurons plays a crucial role for information processing in the brain. Lastly, the book presents an application of the consistency and synchronization property in chaotic semiconductor lasers, namely a type of neuro-inspired information processing referred to as reservoir computing.

Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor lasers and the trends in their development.