Download or read book Contributions l tude th orique des bruits quantiques et classiques dans les amplificateurs Raman distribu s written by Shifeng Jiang and published by . This book was released on 2008 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les amplificateurs Raman à fibres optiques apparaissent aujourd’hui comme une solution très prometteuse pour augmenter la capacité de transmission des réseaux optiques WDM longues distances et hauts débits. Afin de dégager les caractéristiques de ce type d’amplificateurs optiques, ce travail de thèse propose une étude théorique approfondie permettant de comprendre et modéliser les processus de génération de bruit dans les amplificateurs Raman à fibre optiques, et analyser les performances en terme de qualité de transmission. Nous avons tout d’abord établi un modèle quantifié pour l’amplification Raman dans les fibres optiques, à partir d’une étude sur la description quantique de l’optique nonlinéaire macroscopique. Nous avons ensuite reformulé, d’une manière générale, les propriétés quantiques du champ optique, les limites quantiques des dispositifs optiques linéaires et insensibles à la phase, les statistiques quantiques du photocourrant, et les différentes définitions du facteur de bruit pour les dispositifs amplificateurs. Puis, nous avons caractérisé le gain et le facteur de bruit des amplificateurs Raman, permettant de comparer les performances de bruit intrinsèque en fonction de la configuration de pompage choisie. En complément au bruit quantique intrinsèque, nous avons aussi étudié, en établissant et simulant des models stochastiques et vectoriels, deux autres sources de bruit classique importantes dans les amplificateurs Raman, qui sont la rétrodiffusion Rayleigh et le transfert de bruit de la pompe vers le signal. Et les impacts sur les performances des systèmes de ces bruits supplémentaires ont été finalement analysés.
Download or read book Contribution l tude du bruit dans les amplificateurs Raman written by Bruno Bristiel and published by . This book was released on 2006 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce travail a pour but de modéliser et ensuite d'analyser plusieurs sources de bruit dans les amplificateurs Raman distribués. Le formalisme de l'émission spontanée n'est pas utilisé dans cette étude car il présente plusieurs inconsistences non satisfaisantes à notre sens. Aussi, le bruit dans les amplificateurs Raman a été apréhendé via un formalisme semi-classique qui nous permet de représenter conjointement le bruit d'atténuation, le bruit d'amplification et également le transfert de bruit de pompe spécifique au phénomène Raman. De manière plus conventionnelle, le bruit de double rétrodiffusion Rayleigh est également étudié.
Download or read book Bruit basse et moyenne fr quence des amplificateurs optiques distribu s effet Raman written by Cédric Chluda and published by . This book was released on 2006 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'objectif de cette thèse est d'évaluer les contributions en bruit associées aux différents éléments constituant un amplificateur Raman. par A cet effet, nous étudions le bruit associé à la source de pompage dépolarisée, en mettant plus particulièrement l'accent sur l'excès de bruit dû aux deux lasers multimodes qui composent cet étage. Après avoir développé un modèle qualitatif prenant en compte le caractère non-linéaire du gain optique des pompes employées, la source dépolarisée est caractérisée au premier et au second ordre élément par élément puis dans son ensemble. Nous avons alors pu constater qu'outre la contribution du bruit propre aux lasers de pompe, les sources d'alimentation électrique ainsi que divers composants optiques passifs apportaient une contribution non négligeable au bruit total du système de pompage complet. par Parallèlement, nous avons développé un modèle de l'amplificateur Raman à base d'équations de propagation prenant en compte le caractère multimode du système de pompage afin d'évaluer l'impact de l'étalement spectral de la source laser sur la courbe de gain de l'amplificateur. Un ensemble de caractérisations statiques est alors confronté aux résultats de simulation, permettant ainsi de valider le modèle. par Celui-ci est ensuite complété afin d'obtenir la réponse du système en émission spontanée amplifiée, considérée comme le bruit de fond de l'amplificateur, et confronté aux résultats expérimentaux. par Enfin, l'étude des fluctuations vues par le photodétecteur en sortie d'amplificateur est réalisée. La mise en place d'un banc de mesure de bruit d'amplitude permet de valider, par les résultats en bruit obtenus, le développement d'un modèle numérique décrivant efficacement les différents excès de bruit dus à divers phénomènes de battement vus par le photodétecteur en fin de ligne. L'impact de la largeur de raie de la source signal sur le bruit photodétecté ainsi que le report de bruit de pompage sur le signal de sortie sont enfin observés
Download or read book General Relativity and Gravitational Waves written by Joseph Weber and published by Courier Corporation. This book was released on 2004-01-01 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: An internationally famous physicist and electrical engineer, the author of this text was a pioneer in the investigation of gravitational waves. Joseph Weber's General Relativity and Gravitational Waves offers a classic treatment of the subject. Appropriate for upper-level undergraduates and graduate students, this text remains ever relevant. Brief but thorough in its introduction to the foundations of general relativity, it also examines the elements of Riemannian geometry and tensor calculus applicable to this field. Approximately a quarter of the contents explores theoretical and experimental aspects of gravitational radiation. The final chapter focuses on selected topics related to general relativity, including the equations of motion, unified field theories, Friedman's solution of the cosmological problem, and the Hamiltonian formulation of general relativity. Exercises. Index.
Download or read book Single Photon Manipulation written by Keyu Xia and published by BoD – Books on Demand. This book was released on 2020-11-11 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: This short book aims to present basic information about single photons in a quick read but with not many details. For this purpose, it only introduces the basic concept of single photons, the most important method of generating single photons in experiments, and a specific emerging field.
Download or read book Ultra Wide Band Antennas written by Xavier Begaud and published by John Wiley & Sons. This book was released on 2013-03-04 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra Wide Band Technology (UWB) has reached a level of maturity that allows us to offer wireless links with either high or low data rates. These wireless links are frequently associated with a location capability for which ultimate accuracy varies with the inverse of the frequency bandwidth. Using time or frequency domain waveforms, they are currently the subject of international standards facilitating their commercial implementation. Drawing up a complete state of the art, Ultra Wide Band Antennas is aimed at students, engineers and researchers and presents a summary of internationally recognized studies.
Download or read book MIMO written by Alain Sibille and published by Academic Press. This book was released on 2010-12-03 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foreword from Arogyaswami Paulraj, Professor (Emeritus), Stanford University (USA) - The first book to show how MIMO principles can be implemented in today's mobile broadband networks and components - Explains and solves some of the practical difficulties that arise in designing and implementing MIMO systems - Both theory and implementation sections are written in the context of the most recent standards: IEEE 802.11n (WiFi); IEEE 802.16 (WIMAX); 4G networks (3GPP/3GPP2, LTE)
Download or read book Coherent Vibrational Dynamics written by Guglielmo Lanzani and published by CRC Press. This book was released on 2007-11-29 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Remarkable developments in the spectroscopy field regarding ultrashort pulse generation have led to the possibility of producing light pulses ranging from 50 to5 fs and frequency tunable from the near infrared to the ultraviolet range. Such pulses enable us to follow the coupling of vibrational motion to the electronic transitions in molecules and
Download or read book Pervasive Mobile and Ambient Wireless Communications written by Roberto Verdone and published by Springer Science & Business Media. This book was released on 2012-01-02 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reporting the findings of COST 2100, a major European intergovernmental project, this volume offers system designers a good source of guidelines based on channel characterization and measurement-based modeling, as well as worthwhile ideas for future research.
Download or read book Applied Reactor Physics written by Alain Hébert and published by Presses inter Polytechnique. This book was released on 2009 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Theory of Finite Systems written by Jean-Paul Blaizot and published by Mit Press. This book was released on 1986 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive and pedagogical account of the various methods used in the quantum theory of finite systems, including molecular, atomic, nuclear, and particle phenomena. Covering both background material and advanced topics and including nearly 200 problems, Quantum Theory of Finite Systems has been designed to serve primarily as a text and will also prove useful as a reference in research. The first of the book's four parts introduces the basic mathematical apparatus: second quantization, canonical transformations, Wick theorems and the resulting diagram expansions, and oscillator models. The second part presents mean field approximations and the recently developed path integral methods for the quantization of collective modes. Part three develops perturbation theory in terms of both time-dependent Feynman diagrams and time-independent Goldstone diagrams. A fourth part discusses variational methods based on correlated wavefunctions, including spin correlations. The approximation schemes are formulated for fermions and bosons at eigher zero or non-zero temperature. Although the formalism developed applies to both finite and infinite systems, the book stresses those aspects of the theory that are specific to the description of finite systems. Thus special attention is given to mean field approximations, the ensuing broken symmetries, and the associated collective motions such as rotations. Conversely, some specific features of systems with infinite numbers of degrees of freedom (such as the thermodynamic limit, critical phenomena, and the elimination of ultraviolet divergencies) are deliberately omitted. Jean-Paul Blaizot and Georges Ripka are associated with the Centre d'Etudes Nucleaires de Saclay.
Download or read book Governance Regulation and Powers on the Internet written by Eric Brousseau and published by Cambridge University Press. This book was released on 2012-04-23 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: An interdisciplinary survey of the issues surrounding the governance of the Internet.
Download or read book Green Networking written by Francine Krief and published by John Wiley & Sons. This book was released on 2012-12-13 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on green networking, which is an important topic for the scientific community composed of engineers, academics, researchers and industrialists working in the networking field. Reducing the environmental impact of the communications infrastructure has become essential with the ever increasing cost of energy and the need for reducing global CO2 emissions to protect our environment. Recent advances and future directions in green networking are presented in this book, including energy efficient networks (wired networks, wireless networks, mobile networks), adaptive networks (cognitive radio networks, green autonomic networking), green terminals, and industrial research into green networking (smart city, etc.).
Download or read book Transport Theory written by James J. Duderstadt and published by John Wiley & Sons. This book was released on 1979 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Problems after each chapter
Download or read book Nuclear Computational Science written by Yousry Azmy and published by Springer Science & Business Media. This book was released on 2010-04-15 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear engineering has undergone extensive progress over the years. In the past century, colossal developments have been made and with specific reference to the mathematical theory and computational science underlying this discipline, advances in areas such as high-order discretization methods, Krylov Methods and Iteration Acceleration have steadily grown. Nuclear Computational Science: A Century in Review addresses these topics and many more; topics which hold special ties to the first half of the century, and topics focused around the unique combination of nuclear engineering, computational science and mathematical theory. Comprising eight chapters, Nuclear Computational Science: A Century in Review incorporates a number of carefully selected issues representing a variety of problems, providing the reader with a wealth of information in both a clear and concise manner. The comprehensive nature of the coverage and the stature of the contributing authors combine to make this a unique landmark publication. Targeting the medium to advanced level academic, this book will appeal to researchers and students with an interest in the progression of mathematical theory and its application to nuclear computational science.
Download or read book Engineering Acoustics written by Michael Möser and published by Springer Science & Business Media. This book was released on 2009-09-01 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Suitable for both individual and group learning, Engineering Acoustics focuses on basic concepts and methods to make our environments quieter, both in buildings and in the open air. The author’s tutorial style derives from the conviction that understanding is enhanced when the necessity behind the particular teaching approach is made clear. He also combines mathematical derivations and formulas with extensive explanations and examples to deepen comprehension. Fundamental chapters on the physics and perception of sound precede those on noise reduction (elastic isolation) methods. The last chapter deals with microphones and loudspeakers. Moeser includes major discoveries by Lothar Cremer, including the optimum impedance for mufflers and the coincidence effect behind structural acoustic transmission. The appendix gives a short introduction on the use of complex amplitudes in acoustics.
Download or read book The Physics of Nuclear Reactors written by Serge Marguet and published by Springer. This book was released on 2018-02-26 with total page 1462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive volume offers readers a progressive and highly detailed introduction to the complex behavior of neutrons in general, and in the context of nuclear power generation. A compendium and handbook for nuclear engineers, a source of teaching material for academic lecturers as well as a graduate text for advanced students and other non-experts wishing to enter this field, it is based on the author’s teaching and research experience and his recognized expertise in nuclear safety. After recapping a number of points in nuclear physics, placing the theoretical notions in their historical context, the book successively reveals the latest quantitative theories concerning: • The slowing-down of neutrons in matter • The charged particles and electromagnetic rays • The calculation scheme, especially the simplification hypothesis • The concept of criticality based on chain reactions • The theory of homogeneous and heterogeneous reactors • The problem of self-shielding • The theory of the nuclear reflector, a subject largely ignored in literature • The computational methods in transport and diffusion theories Complemented by more than 400 bibliographical references, some of which are commented and annotated, and augmented by an appendix on the history of reactor physics at EDF (Electricité De France), this book is the most comprehensive and up-to-date introduction to and reference resource in neutronics and reactor theory.
