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Dynamic Scenarios In Two State Quantum Dot Lasers

Dynamic Scenarios in Two State Quantum Dot Lasers PDF
Author: André Röhm
Publisher: Springer
ISBN: 3658094028
Size: 48.91 MB
Format: PDF
Category : Science
Languages : en
Pages : 102
View: 2240

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André Röhm investigates the dynamic properties of two-state lasing quantum dot lasers, with a focus on ground state quenching. With a novel semi-analytical approach, different quenching mechanisms are discussed in an unified framework and verified with numerical simulations. The known results and experimental findings are reproduced and parameter dependencies are systematically studied. Additionally, the turn-on dynamics and modulation response curves of two-state lasing devices are presented.

Quantum Dot Lasers

Quantum Dot Lasers PDF
Author: Victor Mikhailovich Ustinov
Publisher: Oxford University Press on Demand
ISBN: 9780198526797
Size: 61.59 MB
Format: PDF
Category : Science
Languages : en
Pages : 290
View: 6036

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A book devoted to the physics and technology of diode lasers based on self-organized quantum dots. It first addresses fundamentals of semiconductor quantum dot fabrication along with structural and electronic properties of quantum dots and secondly, use of self-organized quantum dots in laser structures, their properties and optimization.

Dynamics Of Quantum Dot Lasers

Dynamics of Quantum Dot Lasers PDF
Author: Christian Otto
Publisher: Springer
ISBN: 9783319037851
Size: 18.16 MB
Format: PDF, ePub, Mobi
Category : Technology & Engineering
Languages : en
Pages : 290
View: 6806

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This thesis deals with the dynamics of state-of-the-art nanophotonic semiconductor structures, providing essential information on fundamental aspects of nonlinear dynamical systems on the one hand, and technological applications in modern telecommunication on the other. Three different complex laser structures are considered in detail: (i) a quantum-dot-based semiconductor laser under optical injection from a master laser, (ii) a quantum-dot laser with optical feedback from an external resonator, and (iii) a passively mode-locked quantum-well semiconductor laser with saturable absorber under optical feedback from an external resonator. Using a broad spectrum of methods, both numerical and analytical, this work achieves new fundamental insights into the interplay of microscopically based nonlinear laser dynamics and optical perturbations by delayed feedback and injection.

Quantum Dot Heterostructures

Quantum Dot Heterostructures PDF
Author: Dieter Bimberg
Publisher: John Wiley & Sons
ISBN: 9780471973881
Size: 55.90 MB
Format: PDF, ePub
Category : Science
Languages : en
Pages : 344
View: 2858

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Quantum Dot Heterostructures Dieter Bimberg, Marius Grundmann and Nikolai N. Ledentsov Institute of Solid State Physics, Technische Universität Berlin, Germany Quantum dots are nanometer-size semiconductor structures, and represent one of the most rapidly developing areas of current semiconductor research as increases in the speed and decreases in the size of semiconductor devices become more important. They present the utmost challenge to semiconductor technology, making possible fascinating novel devices. This important new reference book focuses on the key phenomena and principles. Chapter 1 provides a brief account of the history of quantum dots, whilst the second chapter surveys the various fabrication techniques used in the past two decades, and introduces the concept of self-organized growth. This topic is expanded in the following chapter, which presents a broad review of self-organization phenomena at surfaces of crystals. Experimental results on growth of quantum dot structures in many different systems and on their structural characterization are presented in Chapter 4. Basic properties of the dots relate to their geometric structure and chemical composition. Numerical modeling of the electronic and optical properties of real dots is presented in Chapter 5, together with general theoretical considerations on carrier capture, relaxation, recombination and properties of quantum dot lasers. Chapters 6 and 7 summarize experimental results on electronic, optical and electrical properties. The book concludes by disoussing highly topical results on quantum-dot-based photonic devices - mainly quantum dot lasers. Quantum Dot Heterostructures is written by some of the key researchers who have contributed significantly to the development of the field, and have pioneered both the theoretical understanding of quantum dot related phenomena and quantum dot lasers. It is of great interest to graduate and postgraduate students, and to researchers in semiconductor physics and technology and optoelectronics.

Nonlinear Laser Dynamics

Nonlinear Laser Dynamics PDF
Author: Kathy Lüdge
Publisher: John Wiley & Sons
ISBN: 3527639837
Size: 33.87 MB
Format: PDF
Category : Science
Languages : en
Pages : 408
View: 6741

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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.

Quantum Dot Lasers

Quantum Dot Lasers PDF
Author:
Publisher:
ISBN:
Size: 15.40 MB
Format: PDF, Kindle
Category : Diodes, Semiconductor
Languages : en
Pages : 290
View: 2419

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Chirp And Linewidth Characteristics In Semiconductor Quantum Dot Lasers

Chirp and Linewidth Characteristics in Semiconductor Quantum Dot Lasers PDF
Author: Hua Tan
Publisher:
ISBN:
Size: 41.82 MB
Format: PDF
Category :
Languages : en
Pages : 123
View: 5887

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Due to the three dimensional confinement for the carriers, quantum dot lasers are promised to have superior characteristics than quantum well lasers. The direct modulation is playing one of the key roles in ever increasing optical communications, so the characteristics of the semiconductor lasers are of great importance. In this dissertation, the chirp characteristics of the quantum dot lasers are under investigated in details. The spectrum characteristics of the quantum dot lasers are interpreted to understand the reduced thermal conductivity in InGaAs/GaAs quantum dot active region. A thermal conductive model is employed to quantitatively analyze the thermal conductivity in the quantum dots, which is about one order of magnitude less than that in the quantum well lasers. A gain model is built to analyze the dependence of linewidth enhancement factor on duty cycle in quantum dot lasers. Because of the unusual thermal sensitivity of quantum dot active regions, a range of linewidth enhancement factors, from positive, near-zero to negative, could be expected on different duty cycles. A symmetric gain distribution should be approached to achieve near-zero linewidth enhancement factor. 1.3 micron In(Ga)As/GaAs quantum dot DFB lasers fabricated by holography is demonstrated. Lloyd's mirror exposure system is used for the interference lithography. The laser structure is designed, the laser mode distribution is simulated, and the Bragg grating is analyzed. A single mode operation around 1.3 micron is realized in the DFB quantum dot lasers. In DFB lasers, on the shorter wavelength side of the peak gain, the spontaneous emission becomes significant and plays an important role in affecting the spectral linewidth, so care should be taken in using linewidth enhancement factor alone as figure-of-merit to describe the linewidth across the whole spectrum. Finally, the correlation of linewidth to distributed coefficient is discussed and effective facet reflectivity is modeled.

Numerical Modeling Of Narrow Linewidth Quantum Dot Lasers

Numerical Modeling of Narrow linewidth Quantum Dot Lasers PDF
Author: Bjelica, Marko
Publisher: kassel university press GmbH
ISBN: 3737602840
Size: 22.61 MB
Format: PDF, Mobi
Category :
Languages : en
Pages : 135
View: 7148

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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.

Ultrafast Lasers Based On Quantum Dot Structures

Ultrafast Lasers Based on Quantum Dot Structures PDF
Author: Edik U. Rafailov
Publisher: John Wiley & Sons
ISBN: 3527634495
Size: 20.67 MB
Format: PDF, Mobi
Category : Science
Languages : en
Pages : 262
View: 5316

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In this monograph, the authors address the physics and engineering together with the latest achievements of efficient and compact ultrafast lasers based on novel quantum-dot structures and devices. Their approach encompasses a broad range of laser systems, while taking into consideration not only the physical and experimental aspects but also the much needed modeling tools, thus providing a holistic understanding of this hot topic.

Quantum Semiconductor Devices And Technologies

Quantum Semiconductor Devices and Technologies PDF
Author: Tom Pearsall
Publisher: Springer Science & Business Media
ISBN: 1461544513
Size: 15.85 MB
Format: PDF, ePub, Mobi
Category : Technology & Engineering
Languages : en
Pages : 266
View: 4649

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stacked QD structure and is useful for examining the possibility of all optical measurement of stacked QD layers. Optical absorption spectra of self-assembled QDs has been little reported, and further investigation in necessary to study hole-burning memory. 2.5 Summary This chapter describes recent advances in quantum dot fabrication tech nologies, focusing on our self-formed quantum dot technologies including TSR quantum dots and SK-mode self-assembled quantum dots. As is described in this chapter, there are many possible device applications such as quantum dot tunneling memory devices, quantum dot fioating-dot gate FETs, quantum dot lasers, and quantum dot hole-burning memory devices. The quantum dot laser applications seem to be the most practicable among these applications. However, many problems remain to be solved before even this application becomes practical. The most important issue is to of self-assembled quantum dots more pre control the size and position cisely, with an accuracy on an atomic scale. The confinement must be enough to keep the separation energy between quantized energy levels high enough to get high-temperature characteristics. The lasing oscillation frequency should be fixed at 1.3 f.lITl or 1.5 f.lITl for optical communication. Phonon bottleneck problems should be solved by the optimization of device structures. Fortunately, there is much activity in the area of quantum dot lasers and, therefore, many breakthroughs will be made, along with the exploration of other new application areas.

High Power High Efficiency Electron Hole And Unipolar Quantum Dot Lasers

High Power High Efficiency Electron hole and Unipolar Quantum Dot Lasers PDF
Author: Sonia Quadery
Publisher:
ISBN:
Size: 53.36 MB
Format: PDF, ePub, Docs
Category : High power lasers
Languages : en
Pages : 178
View: 5161

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The goal of this research work is to develop and analyze Quantum Dot (QD) lasers aimed at improving high power performance which is crucial for numerous scientific, military and industrial applications. Fundamentally two dissimilar types of lasers are investigated: namely bipolar electron-hole laser and unipolar quantum cascade laser. Planar quantum well (QW) laser diodes are already well-established as commercially available high power semiconductor lasers. However these lasers are unable to deliver power greater few 10's of watts due to reduction in efficiency at longer cavity lengths. This limitation arises from inherent optical losses tied to the two-dimensional density of available states in QWs. A novel approach is proposed here to circumvent this limitation by introducing self-assembled QDs into the laser cavity which due to their delta-like discrete density of states promise to reduce the optical losses by at least an order of magnitude, hence allowing cavity length to increase proportionally. Detailed analysis based on harmonic oscillator model and solution at quasi-equilibrium condition reveal that total internal losses as low as 0.05 per cm−1 can be achieved in a QD laser enabling it to deliver 50 watts of power from each bar while maintaining efficiency close to 90%. In order to take full advantage of the discrete atom-like behavior, it is also of utmost importance to reduce the inhomogeneous broadening of the dot distribution originating from size fluctuation. Experimental data of ultra narrow linewidth InAs quantum dots having linewidth of only 22 meV is presented. Research attempt has been taken to integrate these narrowly distributed dots into a workable structure. Preliminary data shows that these dots are extremely sensitive to the laser material which calls for careful optimization of the entire structure. As for the unipolar QCL, it is shown that internal absorption caused by phonon emission of electrons in a planar quantum cascade laser represents a possible limitation to the maximum operating efficiency. Possibility of reducing this absorption is explored and it is optimistically asserted that introducing QDs into the gain stage of a QCL can eliminate this internal loss mechanism, thus greatly improving high power operating characteristics.

The Physics And Engineering Of Compact Quantum Dot Based Lasers For Biophotonics

The Physics and Engineering of Compact Quantum Dot based Lasers for Biophotonics PDF
Author: Edik U. Rafailov
Publisher: John Wiley & Sons
ISBN: 3527665609
Size: 61.69 MB
Format: PDF, Kindle
Category : Science
Languages : en
Pages : 264
View: 1778

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Written by a team of European experts in the field, this book addresses the physics, the principles, the engineering methods, and the latest developments of efficient and compact ultrafast lasers based on novel quantum-dot structures and devices, as well as their applications in biophotonics. Recommended reading for physicists, engineers, students and lecturers in the fields of photonics, optics, laser physics, optoelectronics, and biophotonics.

Nonlinear And Nonequilibrium Dynamics Of Quantum Dot Optoelectronic Devices

Nonlinear and Nonequilibrium Dynamics of Quantum Dot Optoelectronic Devices PDF
Author: Benjamin Lingnau
Publisher: Springer
ISBN: 3319258052
Size: 57.34 MB
Format: PDF, Kindle
Category : Technology & Engineering
Languages : en
Pages : 193
View: 3038

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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.

Photonics Of Quantum Dot Nanomaterials And Devices

Photonics of Quantum dot Nanomaterials and Devices PDF
Author: Ortwin Hess
Publisher: World Scientific
ISBN: 1848165226
Size: 12.49 MB
Format: PDF, ePub
Category : Electronic books
Languages : en
Pages : 171
View: 1663

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Quantum dot nano structures are interesting for applications in information technology and play a growing role in data storage, medical and biological applications. Understanding quantum nanomaterials is thus the key for the conception and optimization of novel structures. This monograph gives an overview of the theory and introduces the concepts of advanced computational modelling of quantum dot nanomaterials and devices ranging from phenomenological models up to fully quantum theoretical description.

Sensitivity Of Quantum Dot Lasers To External Optical Feedback

Sensitivity of Quantum Dot Lasers to External Optical Feedback PDF
Author: David Vincent O'Brien
Publisher:
ISBN:
Size: 32.87 MB
Format: PDF, Docs
Category : Lasers
Languages : en
Pages : 139
View: 1198

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Quantum dots are man-made nanostructures that typically vary from 10's to 100's of nonometers in size. These dimensions are of the order of the De Broglie wavelength of the electron, and so electrons confined in these structures exhibit electronic and optical characteristics that are similar to those in atoms. These low dimensional semiconductor structures have attracted considerable interest both for their fundamental properties and for their potential applications in micro and optoelectronics. Possible applications that have been suggested include single electron transistors, various photonic devices and as components for quantum computing systems. In particular, laser diodes incorporating quantum dot active regions have been studied extensively in the last few years. Many theoretical studies have shown the potential benefits of these devices over more conventional semiconductor laser diodes. From the atom-like density of states a symmetric gain spectrum is predicted, which eliminates some problems inherent in other semiconductor lasers, such as self focusing and filamentation in broad area devices, antiguiding in narrow stripe devices and chirp under high speed modulation. These and other effects in semiconductor lasers have been characterized in terms of the a-factor. This parameter has been predicted to approach zero for quantum dot devices lasing in the ground state. Lasers incorporating quantum dot active regions have the potential for the improved performance of gas lasers and some other laser systems, while maintaining the advantage of smaller size and ease of manufacture that have made semiconductor lasers so widespread. Recent advances in the fabrication of quantum dot materials have made the manufacture of high quality quantum dot material more feasible, bringing the potential applications that much closer. With improved fabrication techniques, dots of similar, size, shape, strain and consistency can be achieved, with device performance improving alongside these developments. As the quality of the material improves, it is possible to study more closely the difference between real life devices and the theoretical abstractions that predict their enhanced performance. Inhomogeneous broadening of the gain region, Coulomb effects, relaxation mechanisms and rates involved all give rise to a more complex system than the sum of a series of two level systems that was originally visualized as the active region arising from a quantum dot ensemble.