Download or read book Etude et applications des amplificateurs param triques fibre optique written by Armand Vedadi and published by . This book was released on 2008 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Depuis l'avènement en Perse, il y a 2500 ans, du service postal, la capacité à transmettre un maximum d'information sur une longue distance et en un minimum de temps s'avère être une des quêtes de l'Homme. Aujourd'hui, les moyens de télécommunications modernes font partie de notre quotidien et nous permettent de partager quasi-instantanément de la voix, de l'image ou du texte avec un interlocuteur situé à des milliers de kilomètres. Le cadre général dans lequel s'insère ce manuscrit de thèse est celui de l'étude de la couche physique des télécommunications, mais de façon plus précise, celui de la recherche d'outils de traitement tout-optique de l'information destinés particulièrement aux futurs systèmes de transmission à très haut débit. En effet, de nombreuses recherches ces dernières années ont montré la variété d'applications possibles à partir de l'amplification paramétrique, une nouvelle technique d'amplification sur fibre optique offrant une très grande bande passante. Nous présentons dans ce manuscrit une étude théorique des amplificateurs paramétriques utilisant deux lasers de pompe. Nous analyserons également le bruit et la distorsion des signaux de télécommunications apportés par la modulation de phase des pompes, requise pour supprimer la rétro-diffusion Brillouin stimulée dans toute fibre optique. Nous donnerons la démonstration théorique que deux ondes pompes modulées en opposition de phase annulent toute distorsion des signaux. Nous présenterons également une mise en oeuvre expérimentale d'un amplificateur paramétrique optique, intégrant un nouveau modulateur de phase double réalisé en partenariat avec la société Photline Technologies. Celui-ci nous a permis de démontrer une qualité d'amplification optique ainsi qu'une conversion de longueur d'onde quasi-transparente. La troisième partie présente ce qui constitue, à notre connaissance, la première mesure distribuée du gain paramétrique le long de la fibre optique servant de milieu amplificateur. Ces travaux ont été réalisés en collaboration avec l'Ecole Fédérale Polytechnique de Lausanne (EPFL), en Suisse. Ils sont basés sur l'analyse Brillouin dans le domaine temporel. La quatrième et dernière partie de ce manuscrit relate une étude théorique et numérique d'une boucle à réplication d'impulsion laser intégrant un amplificateur paramétrique. Ces travaux ont été réalisés dans le cadre d'un contrat avec le Commissariat à l'Energie Atomique (CEA). L'originalité de cette étude réside dans l'exploitation des amplificateurs paramétriques dans la fenêtre de longueurs d'ondes autour de 1 ~m en utilisant des fibres à cristal photonique.
Download or read book Etude des amplificateurs param triques fibre optique pour leur utilisation dans les syst mes de transmissions optiques haut d bit multiplex es en longueur d ondes written by Anne Legrand and published by . This book was released on 2005 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pour augmenter la quantité d'information transmise par les réseaux de télécommunications optiques, les équipementiers souhaitent étendre la bande spectrale utilisée. Ceci nécessite de nouveaux amplificateurs optiques. Les amplificateurs paramétriques à fibre optique présentent l'avantage de produire une large bande de gain. Au cours de cette thèse, leurs conditions de fonctionnement ont été étudiées afin de vérifier leur adéquation aux systèmes de transmission optique. Cette étude a montré qu'un amplificateur paramétrique peut produire une bande de gain répondant aux exigences des transmissions multiplexées en longueur d'onde. De plus, un facteur de bruit de 4 dB a été mesuré électriquement. Par contre, une attention particulière doit être portée au dispositif de pompage optique. Ce travail a permis de mieux définir ses caractéristiques essentielles pour résister à l'effet néfaste de la diffusion Brillouin et assurer une amplification faible bruit et sans distorsion des canaux
Download or read book Etude r alisation d amplificateurs optiques fibre fluor e dop e l erbium et applications aux syst mes de transmission optique written by Houmed Ibrahim and published by . This book was released on 1993 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: LE THEME DE CETTE THESE SE SITUE DANS LE CADRE DES TRANSMISSIONS OPTIQUES. LES COMPOSANTS ETUDIES ET REALISES SONT DEUX TYPES D'AMPLIFICATEURS A FIBRE FLUOREE DOPEE ERBIUM, LE PREMIER OPERANT DANS LA FENETRE 1550 NM, LE SECOND FONCTIONNANT DANS L'INFRAROUGE MOYEN AUTOUR DE 2720 NM. LE PREMIER FIL CONDUCTEUR DE L'ETUDE A ETE L'OPTIMISATION DES DIFFERENTS PARAMETRES OPTOGEOMETRIQUES DE LA FIBRE FLUOREE AFIN DE MAXIMISER LE GAIN DE L'AMPLIFICATEUR OPTIQUE ET D'ACCROITRE LE RENDEMENT DE CONVERSION DE L'ENERGIE DU POMPAGE OPTIQUE EN GAIN NET. APRES L'OPTIMISATION DE LA FIBRE AMPLIFICATRICE A 1,5 M, LES PERFORMANCES DE CET AMPLIFICATEUR OPTIQUE A FIBRE FLUOREE ONT ETE EVALUEES DANS UN SYSTEME DE TRANSMISSION NUMERIQUE HAUT DEBIT PUIS DANS UN SYSTEME DE TELEDISTRIBUTION ANALOGIQUE. AFIN D'AUGMENTER LE GAIN DE L'AMPLIFICATEUR OPTIQUE A 2,7 M, LE VIDAGE DU NIVEAU 4I#1#3#/#2 PAR LE BIAIS D'UNE LONGUEUR D'ONDE DE POMPE ADEQUATE QUI CREE UNE ABSORPTION PAR ETATS EXCITES, OU PAR LE CODOPAGE DE L'ER#3#+ AVEC DU PRASEODYME, A ETE ETUDIE. AUTOUR DE LA LONGUEUR D'ONDE 1,5 M, L'OPTIMISATION DES DIFFERENTES CARACTERISTIQUES DE LA FIBRE FLUOREE DOPEE ER#3#+ A PERMIS D'ATTEINDRE UN GAIN PETIT SIGNAL DE 31 DB ET AVEC UNE FIBRE FLUOREE DE GRANDE OUVERTURE NUMERIQUE UN RENDEMENT DE 3,4 DB/MW A ETE MESURE. DEUX METHODES DE MESURE DE BRUIT OPTIQUE ET ELECTRIQUE ONT ETE MISES AU POINT. UN MODULE AMPLIFICATEUR OPTIQUE A FIBRE FLUOREE A 1,5 M ET A GAIN PLAT A ETE REALISE. LES PRINCIPALES CARACTERISTIQUES DE L'AMPLIFICATEUR: GAIN PETIT SIGNAL, PUISSANCE DE SORTIE, FACTEUR DE BRUIT SONT ANALYSEES DANS LES TROIS SCHEMAS CLASSIQUES POST-AMPLIFICATION, AMPLIFICATION EN LIGNE ET PREAMPLIFICATION. L'INSERTION DE CE MODULE AMPLIFICATEUR DANS UN SYSTEME DE TRANSMISSION NUMERIQUE A 5 GBIT/S A PERMIS D'ACCROITRE LA PORTEE DE LA LIAISON POINT A POINT. DANS UN SYSTEME DE TELEDISTRIBUTION ANALOGIQUE A 1,5 M, L'INTERET DU GAIN SPECTRAL PLAT DE L'AMPLIFICATEUR A FIBRE FLUOREE A ETE DEMONTRE
Download or read book Quantum Mechanics Volume 3 written by Claude Cohen-Tannoudji and published by John Wiley & Sons. This book was released on 2019-12-16 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new, third volume of Cohen-Tannoudji's groundbreaking textbook covers advanced topics of quantum mechanics such as uncorrelated and correlated identical particles, the quantum theory of the electromagnetic field, absorption, emission and scattering of photons by atoms, and quantum entanglement. Written in a didactically unrivalled manner, the textbook explains the fundamental concepts in seven chapters which are elaborated in accompanying complements that provide more detailed discussions, examples and applications. * Completing the success story: the third and final volume of the quantum mechanics textbook written by 1997 Nobel laureate Claude Cohen-Tannoudji and his colleagues Bernard Diu and Franck Laloë * As easily comprehensible as possible: all steps of the physical background and its mathematical representation are spelled out explicitly * Comprehensive: in addition to the fundamentals themselves, the books comes with a wealth of elaborately explained examples and applications Claude Cohen-Tannoudji was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris where he also studied and received his PhD in 1962. In 1973 he became Professor of atomic and molecular physics at the Collège des France. His main research interests were optical pumping, quantum optics and atom-photon interactions. In 1997, Claude Cohen-Tannoudji, together with Steven Chu and William D. Phillips, was awarded the Nobel Prize in Physics for his research on laser cooling and trapping of neutral atoms. Bernard Diu was Professor at the Denis Diderot University (Paris VII). He was engaged in research at the Laboratory of Theoretical Physics and High Energy where his focus was on strong interactions physics and statistical mechanics. Franck Laloë was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris. His first assignment was with the University of Paris VI before he was appointed to the CNRS, the French National Research Center. His research was focused on optical pumping, statistical mechanics of quantum gases, musical acoustics and the foundations of quantum mechanics.
Download or read book Theory of X Ray Diffraction in Crystals written by William H. Zachariasen and published by Dover Publications. This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This classic by one of the great figures in x-ray structure analysis provides a vigorous mathematical treatment of its subject. Addresses such fundamentals as crystal faces and edges, the lattice postulate, lattice rows and panes, as well as point, translation, and space groups. 1945 edition.
Download or read book Thermal Analysis written by Hans Georg Wiedemann and published by . This book was released on 1972 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics of Sliding Friction written by Bo N.J. Persson and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of sliding friction is one of the oldest problems in physics, and certainly one of the most important from a practical point of view. Low-friction surfaces are in increasingly high demand for high-tech components such as computer storage systems, miniature motors, and aerospace devices. It has been estimated that about 5% of the gross national product in the developed countries is "wasted" on friction and the related wear. In spite of this, remarkable little is understood about the fundamental, microscopic processes responsible for friction and wear. The topic of interfacial sliding has experienced a major burst of in terest and activity since 1987, much of which has developed quite independently and spontaneously. This volume contains contributions from leading scientists on fundamental aspects of sliding friction. Some problems considered are: What is the origin of stick-and-slip motion? What is the origin of the rapid processes taking place within a lub at low sliding velocities? On a metallic surface, is the rication layer electronic or phononic friction the dominating energy dissipation pro cess? What is the role (if any) of self-organized criticality in sliding friction? How thick is the water layer during sliding on ice and snow? These and other questions raised in this book are of course only part ly answered: the topic of sliding friction is still in an early state of development.
Download or read book Critical Technologies Plan written by and published by . This book was released on 1989 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the First International Congress of Radiation Protection written by and published by . This book was released on 1968 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Decisions of the Commissioner of Patents written by and published by . This book was released on 1871 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recursive Functions written by Rózsa Péter and published by . This book was released on 1967 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Color Television Receivers written by and published by . This book was released on 1978 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Report to the President on investigation no. 332-95 under section 332 of the Tariff Act of 1930, as amended.
Download or read book Routledge International Handbook of Ignorance Studies written by Matthias Gross and published by Routledge. This book was released on 2015-05-15 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Once treated as the absence of knowledge, ignorance today has become a highly influential topic in its own right, commanding growing attention across the natural and social sciences where a wide range of scholars have begun to explore the social life and political issues involved in the distribution and strategic use of not knowing. The field is growing fast and this handbook reflects this interdisciplinary field of study by drawing contributions from economics, sociology, history, philosophy, cultural studies, anthropology, feminist studies, and related fields in order to serve as a seminal guide to the political, legal and social uses of ignorance in social and political life. Chapter 33 of this book is freely available as a downloadable Open Access PDF under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license available here: https://tandfbis.s3-us-west-2.amazonaws.com/rt-files/docs/Open+Access+Chapters/9780415718967_oachapter33.pdf
Download or read book A Fundamental Basis for Measurements of Length written by Henry Walter Bearce and published by . This book was released on 1926 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Genus Alexandrium Halim Dinoflagellata written by Enrique Balech and published by . This book was released on 1995 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant Ecology written by Unesco and published by . This book was released on 1955 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Historical Dictionary of Iran written by John Henry Lorentz and published by Historical Dictionaries of Asia, Oceania, and the Middle East. This book was released on 2007 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides an overview of specific events, movements, people, political and social groups, places, trends, and chronology. Allows for considerable exploration of a number of historical and contemporary topics and issues. The modern period, defined as 1800-present, is covered extensively.
