Download or read book Modeling of DFB Surface Emitting Lasers and Semiconductor Laser Arrays written by Shing Man Lee and published by . This book was released on 1991 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical modeling of novel semiconductor laser systems, i.e., distributed-feedback (DFB) surface emitting lasers and semiconductor laser arrays, is presented. The DFB surface emitting lasers can produce stable single-mode outputs even under high bit-rate direct modulation and form two-dimensional laser arrays. A simple and accurate analytical model using the coupled-mode theory is developed to describe these surface emitting lasers. Due to the simplicity of the model, the desired laser output characteristics, i.e., low threshold condition, large side mode suppression ratio, and stable and low noise Bragg-mode outputs, can be obtained by systematically optimizing the device length, optical coupling and phase shifter in the device. The nonplanar laser arrays are of much interest because of their simple fabricating procedures and very high output power. A theoretical study is performed to understand the efficiency and far-field and near-field patterns. A number of important physical mechanisms for high power semiconductor laser operations are studied using a self-consistent model. These include the two-dimensional current spreading in the cladding layers, the coupling between the carrier distribution and the photon distribution, and the carrier saturation effects at high power operation. The mesas, bends, and grooves are treated as adjacent waveguides, each described by the effective index method. The output field patterns in the nonplanar laser structures are composed of a linear combination of the individual waveguide modes. The multimode operation in practical devices can be explained by spatial hole burning effects, nonuniform current injection, and competition for available carriers in the neighboring waveguides between different optical modes. The possibility of obtaining phase-locked output by reducing the groove depth is also investigated. A finite-difference time-domain (FDTD) model is used to study the radiation losses due to the bend. A groove depth as small as 0.1 $mu$m can be used for maximum optical coupling while the bending loss is still large enough to suppress the lateral lasing operation in the nonplanar laser array. The highest semiconductor laser output powers have been achieved by the laser arrays employing optical turning mirrors. The effects of the rough turning mirrors on the laser array performance are estimated using the FDTD method. A number of steps are employed to reduce the computation time on these very large mirrors (about sixty wavelengths) to make the FDTD model a possible computer-aided design tool. The computation time is reduced by a factor of twenty.
Download or read book Analysis and Design of Vertical Cavity Surface Emitting Lasers written by S. F. Yu and published by John Wiley & Sons. This book was released on 2003-09-04 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: A practical, hands-on guidebook for the efficient modeling of VCSELs Vertical Cavity Surface Emitting Lasers (VCSELs) are a unique type of semiconductor laser whose optical output is vertically emitted from the surface as opposed to conventional edge-emitting semiconductor lasers. Complex in design and expensive to produce, VCSELs nevertheless represent an already widely used laser technology that promises to have even more significant applications in the future. Although the research has accelerated, there have been relatively few books written on this important topic. Analysis and Design of Vertical Cavity Surface Emitting Lasers seeks to encapsulate this growing body of knowledge into a single, comprehensive reference that will be of equal value for both professionals and academics in the field. The author, a recognized expert in the field of VCSELs, attempts to clarify often conflicting assumptions in order to help readers achieve the simplest and most efficient VCSEL models for any given problem. Highlights of the text include: * A clear and comprehensive theoretical treatment of VCSELs * Detailed derivations for understanding the operational principles of VCSELs * Mathematical models for the investigation of electrical, optical, and thermal properties of VCSELs * Case studies on the mathematical modeling of VCSELs and the implementation of simulation programs
Download or read book Dynamics of Distributed Feedback Lasers and Semiconductor Laser Arrays written by Yuan-Hwang Liao and published by . This book was released on 1997 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Diode Laser Arrays written by Dan Botez and published by Cambridge University Press. This book was released on 2005-11-24 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the fundamental principles and applications of semiconductor diode laser arrays. All of the major types of arrays are discussed in detail, including coherent, incoherent, edge- and surface-emitting, horizontal- and vertical-cavity, individually addressed, lattice- matched and strained-layer systems. The initial chapters cover such topics as lasers, amplifiers, external-cavity control, theoretical modeling, and operational dynamics. Spatially incoherent arrays are then described in detail, and the uses of vertical-cavity surface emitter and edge-emitting arrays in parallel optical-signal processing and multi-channel optical recording are discussed. Researchers and graduate students in solid state physics and electrical engineering studying the properties and applications of such arrays will find this book invaluable.
Download or read book Study of Phase Locked Diode Laser Array and DFB DBR Surface Emitting Laser Diode written by Wei Hsin and published by . This book was released on 1990 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Modeling of Narrow linewidth Quantum Dot Lasers written by Bjelica, Marko and published by kassel university press GmbH. This book was released on 2017-01-01 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quantization of the active laser medium has enabled numerous advances in fiber-optic communications, e.g., higher efficiency of laser diodes, higher modulation bandwidth, lower spectral linewidth of the emitted signal. In recent years the quantum dot lasers have demonstrated a strong potential to continue this trend, therefore, by progressing from standard quantum well to quantum dot designs, it can be expected that the quantum dot lasers will play an increasingly important role in future fiber-optic communications. The research work presented in this dissertation seeks to further develop the quantum dot laser designs and improve the understanding of complex operating conditions affecting the laser linewidth. This is achieved by developing a comprehensive laser simulator, that was applied to design and simulation of edge-emitting lasers and laser arrays. As a result, the optimized laser diodes have demonstrated a significantly lower linewidth compared to equivalent quantum well designs. Due to their narrow linewidth, the realized photonic devices can be a viable solution for high bit rate fiber-optic networks.
Download or read book Surface Emitting Semiconductor Lasers and Arrays written by Gary A. Evans and published by . This book was released on 1993 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews all the basic types of surface emitting semiconductor lasers, including vertical cavity, etched-mirror integrated beam deflectors and grating out-coupled devices. The book also addresses such topics as edge-emitting arrays, thermal management and coherence.
Download or read book Distributed Feedback Semiconductor Lasers written by John E. Carroll and published by IET. This book was released on 1998 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concentrating on presenting a thorough analysis of DFB lasers from a level suitable for research students, this book emphasises and gives extensive coverage of computer aided modeling techniques.
Download or read book InGaAsP InP Based 1 3 1 55 Micron Vertical Cavity Surface Emitting Lasers for Wavelength Division Multiplexed High Speed Distributed Computing Phase 1 written by M. K. Kilcoyne and published by . This book was released on 1993 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wavelength division multiplexed communication systems are becoming increasingly attractive for maximizing the data capacity of long range fiber optic links. Currently, distributed feedback (DFB) semiconductor lasers must be used due to the system requirements of precise single frequency lasers. The high cost of DFB lasers and associated control circuitry has made these systems too expensive for wide acceptance. In this research the possibility of using wavelength division multiplexed arrays of single 1.55 micron InGaAsP vertical cavity surface emitting lasers has been analyzed. The laser arrays have the potential to dramatically reduce the costs of sources compared with distributed feedback laser arrays. This research has focused on the technologies of wafer fusion, step etching and current constriction to develop designs that meet wavelength division multiplexed system requirements. Experiments and modeling has shown that 4x4 arrays of vertical cavity lasers spaced 2nm apart in wavelength are a realistic goal. The sixteen lasers would each be capable of launching single mode powers above lmw into a fiber at drive currents below 8mA. Vertical cavity lasers, Distributed computing, Wavelength division multiplexing, InGaAsP lasers.
Download or read book 3d Simulation of Vertical Cavity Surface Emitting Lasers written by Peter Nyakas and published by LAP Lambert Academic Publishing. This book was released on 2010-08 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vertical-cavity surface-emitting lasers are promising devices on the semiconductor laser market, and offer numerous advantages over edge-emitters in the low power regime. Physics-based comprehensive modeling allows one to shorten the development period of future products and to reduce the design costs. These devices are sometimes noncircular, either owing to anisotropic oxidation speed or to achieve special characteristics, such as high-power single-mode output. Problems arising with complex structures call for three-dimensional numerical solutions. This book reviews the simulation methods for vertical-cavity surface-emitting lasers and provides novel approaches to investigate their more challenging variants. Electrical, thermal and optical properties are demonstrated on illustrative examples. The analysis helps to get insight into these exciting lasers, and should be especially useful to professionals in telecommunication and modeling fields.
Download or read book Tailoring the Emission of Stripe array Diode Lasers with External Cavities to Enable Nonlinear Frequency Conversion written by Andreas Jechow and published by Universitätsverlag Potsdam. This book was released on 2009 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: A huge number of applications require coherent radiation in the visible spectral range. Since diode lasers are very compact and efficient light sources, there exists a great interest to cover these applications with diode laser emission. Despite modern band gap engineering not all wavelengths can be accessed with diode laser radiation. Especially in the visible spectral range between 480 nm and 630 nm no emission from diode lasers is available, yet. Nonlinear frequency conversion of near-infrared radiation is a common way to generate coherent emission in the visible spectral range. However, radiation with extraordinary spatial temporal and spectral quality is required to pump frequency conversion. Broad area (BA) diode lasers are reliable high power light sources in the near-infrared spectral range. They belong to the most efficient coherent light sources with electro-optical efficiencies of more than 70%. Standard BA lasers are not suitable as pump lasers for frequency conversion because of their poor beam quality and spectral properties. For this purpose, tapered lasers and diode lasers with Bragg gratings are utilized. However, these new diode laser structures demand for additional manufacturing and assembling steps that makes their processing challenging and expensive. An alternative to BA diode lasers is the stripe-array architecture. The emitting area of a stripe-array diode laser is comparable to a BA device and the manufacturing of these arrays requires only one additional process step. Such a stripe-array consists of several narrow striped emitters realized with close proximity. Due to the overlap of the fields of neighboring emitters or the presence of leaky waves, a strong coupling between the emitters exists. As a consequence, the emission of such an array is characterized by a so called supermode. However, for the free running stripe-array mode competition between several supermodes occurs because of the lack of wavelength stabilization. This leads to power fluctuations, spectral instabilities and poor beam quality. Thus, it was necessary to study the emission properties of those stripe-arrays to find new concepts to realize an external synchronization of the emitters. The aim was to achieve stable longitudinal and transversal single mode operation with high output powers giving a brightness sufficient for efficient nonlinear frequency conversion. For this purpose a comprehensive analysis of the stripe-array devices was done here. The physical effects that are the origin of the emission characteristics were investigated theoretically and experimentally. In this context numerical models could be verified and extended. A good agreement between simulation and experiment was observed. One way to stabilize a specific supermode of an array is to operate it in an external cavity. Based on mathematical simulations and experimental work, it was possible to design novel external cavities to select a specific supermode and stabilize all emitters of the array at the same wavelength. This resulted in stable emission with 1 W output power, a narrow bandwidth in the range of 2 MHz and a very good beam quality with M²<1.5. This is a new level of brightness and brilliance compared to other BA and stripe-array diode laser systems. The emission from this external cavity diode laser (ECDL) satisfied the requirements for nonlinear frequency conversion. Furthermore, a huge improvement to existing concepts was made. In the next step newly available periodically poled crystals were used for second harmonic generation (SHG) in single pass setups. With the stripe-array ECDL as pump source, more than 140 mW of coherent radiation at 488 nm could be generated with a very high opto-optical conversion efficiency. The generated blue light had very good transversal and longitudinal properties and could be used to generate biphotons by parametric down-conversion. This was feasible because of the improvement made with the infrared stripe-array diode lasers due to the development of new physical concepts.
Download or read book Coupled Wave Analysis of Two dimensional Second Order Surface emitting Distributed Feedback Lasers written by Yangfei Shen and published by . This book was released on 2016 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: A distributed feedback laser (DFB) is a type of semiconductor laser where the cavity is periodically structured as a diffraction grating. This allows the same grating region to act as a resonator, out-coupler and the gain region simultaneously. While conventional DFB lasers emit light along its edges, by modifying the grating structure, it is possible to make the output appear from the top surface. This is known as the surface-emitting DFB laser. This thesis will discuss the case in which a two-dimensional grating (which consists of a 2D grid of holes or pillars) etched into the top cladding surface of the waveguide. The thesis consists of four main parts. For the first part, we give the background principles and the coupled wave equations with radiation modes. In the second part, we derive the equations for a waveguide that utilizes a grating strip for guidance. The effective index of this guide is then used in the 2D DFB crossed grating structure. The third part begins with calculations of a particular GaAs:GaAlAs waveguide geometry with a grating. We present the fundamental resonant modes by utilizing the numerical shooting method. Then, the matrix solution method is applied in the calculation of the higher order guided and radiation modes. In the last part, we solve the transcendental equations for the eigenvalues to get the threshold gain and near field radiation pattern from the DFB surface.
Download or read book Laser Diode Technology and Applications written by and published by . This book was released on 1992 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design simulation and analysis of laterally longitudinally non uniform edge emitting GaAs based diode lasers Band 73 written by Jan-Philipp Koester and published by Cuvillier Verlag. This book was released on 2023-09-19 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edge-emitting quantum-well diode lasers based on GaAs combine a high conversion efficiency, a wide range of emission wavelengths covering a span from 630 nm to 1180 nm, and the ability to achieve high output powers. The often used longitudinal-invariant Fabry-Pérot-type resonators are easy to design but often lead to functionality or performance limitations. In this work, the application of laterally-longitudinally non-uniform resonator configurations is explored as a way to reduce unwanted and performance-limiting effects. The investigations are carried out on existing and entirely newly developed laser designs using dedicated simulation tools. These include a sophisticated time-dependent laser simulator based on a traveling-wave model of the optical fields in the lateral-longitudinal plane and a Maxwell solver based on the eigenmode expansion method for the simulation of passive waveguides. Whenever possible, the simulation results are compared with experimental data. Based on this approach, three fundamentally different laser types are investigated: • Dual-wavelength lasers emitting two slightly detuned wavelengths around 784 nm out of a single aperture • Ridge-waveguide lasers with tapered waveguide and contact layouts that emit light of a wavelength of around 970 nm • Broad-area lasers with slightly tapered contact layouts emitting at 910 nm The results of this thesis underline the potential of lateral-longitudinal non-uniform laser designs to increase selected aspects of device performance, including beam quality, spectral stability, and output power.
Download or read book Vertical Cavity Surface Emitting Laser Devices written by Herbert Li and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explains in detail the basics, theory, design, fabrication, and operation of vertical-cavity surface-emitting lasers. All the chapters are written by pioneers and key experts who have exclusive access to the most up-to-date innovations in the respective fields.
Download or read book Spatio Temporal Modeling and Device Optimization of Passively Mode Locked Semiconductor Lasers written by Stefan Meinecke and published by Springer Nature. This book was released on 2022-03-26 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates passively mode-locked semiconductor lasers by numerical methods. The understanding and optimization of such devices is crucial to the advancement of technologies such as optical data communication and dual comb spectroscopy. The focus of the thesis is therefore on the development of efficient numerical models, which are able both to perform larger parameter studies and to provide quantitative predictions. Along with that, visualization and evaluation techniques for the rich spatio-temporal laser dynamics are developed; these facilitate the physical interpretation of the observed features. The investigations in this thesis revolve around two specific semiconductor devices, namely a monolithically integrated three-section tapered quantum-dot laser and a V-shaped external cavity laser. In both cases, the simulations closely tie in with experimental results, which have been obtained in collaboration with the TU Darmstadt and the ETH Zurich. Based on the successful numerical reproduction of the experimental findings, the emission dynamics of both lasers can be understood in terms of the cavity geometry and the active medium dynamics. The latter, in particular, highlights the value of the developed simulation tools, since the fast charge-carrier dynamics are generally not experimentally accessible during mode-locking operation. Lastly, the numerical models are used to perform laser design explorations and thus to derive recommendations for further optimizations.
Download or read book Science Abstracts written by and published by . This book was released on 1995 with total page 1360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
