Download or read book Mod lisation de diodes laser puits quantiques contraints GaInAs mettant dans la gamme des 980 nm written by Hélène Leymarie (physicienne) and published by . This book was released on 1994 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES TRAVAUX REPORTES DANS CE MEMOIRE CONCERNENT LES METHODES DE MODELISATION ET DE CONCEPTION DES DIODES LASER A PUITS QUANTIQUES CONTRAINTS GAINAS EMETTANT DANS LA GAMME DES 980 NM, DISPOSITIFS TOUT PARTICULIEREMENT ADAPTES AU POMPAGE DES AMPLIFICATEURS OPTIQUES A FIBRE DE SILICE DOPEE ERBIUM UTILISES DANS LES TELECOMMUNICATIONS OPTIQUES A LONGUES DISTANCES. LE LOGICIEL CADILAC (CONCEPTION DE DIODES LASER A PUITS QUANTIQUES CONTRAINTS), QUI A ETE DEVELOPPE DANS CE BUT, PERMET DE DETERMINER A PARTIR DES PARAMETRES STRUCTURAUX DU COMPOSANT LA CARACTERISTIQUE GAIN-COURANT, LA LONGUEUR D'ONDE D'EMISSION, LA DENSITE DE COURANT DE SEUIL, LES DIAGRAMMES DE CHAMP PROCHE ET DE CHAMP LOINTAIN. LE MODELE QUI SOUS-TEND CE LOGICIEL PREND EN COMPTE L'INFLUENCE DE LA CONTRAINTE SUR LA MODIFICATION DE LA LARGEUR DE BANDE INTERDITE ET SUR LA FORME DES DIFFERENTES BANDES DE VALENCE DU MATERIAU PUITS, LES EFFETS DE RENORMALISATION DE BANDE INTERDITE, LES EFFETS DE RELAXATION INTRABANDE SUR L'ELARGISSEMENT DU SPECTRE DE GAIN. CET OUTIL DE CONCEPTION EST MIS EN UVRE POUR L'ETUDE DES PROPRIETES DE DIODES LASER GAINAS/GAAS/GAALAS AFIN D'EN DEDUIRE LES TYPES DE STRUCTURES PRESENTANT LES MEILLEURS COMPROMIS DENSITE DE COURANT DE SEUIL FAIBLE DIVERGENCE DU DIAGRAMME DE RAYONNEMENT MOINDRE SENSIBILITE AUX DISPERSIONS TECHNOLOGIQUES DES PARAMETRES STRUCTURAUX. IL EST AUSSI UTILISE POUR L'ANALYSE DE COMPOSANTS DE TYPE GAINAS/GAINASP/GAINP, QUI NE COMPORTENT AUCUN ALLIAGE A BASE D'ALUMINIUM EN VUE D'ACCROITRE LEUR FIABILITE: UNE ATTENTION PARTICULIERE EST PORTEE A L'ANALYSE DE L'INFLUENCE DE LA COMPOSITION DE L'ALLIAGE GAINASP DE BARRIERE EN VUE D'OPTIMISER LE CONFINEMENT DES PORTEURS DANS LE PUITS ET LA DIVERGENCE DU DIAGRAMME DE RAYONNEMENT SANS PENALISER LA VALEUR DE LA DENSITE DE COURANT DE SEUIL. ENFIN UNE COMPARAISON THEORIE-EXPERIENCE CONCERNANT LA LONGUEUR D'ONDE D'EMISSION, LE COURANT DE SEUIL, LA DIVERGENCE DU DIAGRAMME DE RAYONNEMENT ET PORTANT SUR PLUSIEURS SERIES DES DEUX TYPES DE DISPOSITIFS A PERMIS DE VALIDER LE BIEN FONDE DES MODELES THEORIQUES DEVELOPPES
Download or read book CONTRIBUTION A LA MODELISATION DE DIODES LASER A PUITS QUANTIQUES CONTRAINTS POUR TELECOMMUNICATIONS OPTIQUES written by Olivier Gilard and published by . This book was released on 1999 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES TRAVAUX REPORTES DANS CE MEMOIRE CONCERNENT LA MODELISATION ET L'ANALYSE EXPERIMENTALE DE DIODES LASER POUR TELECOMMUNICATIONS PAR FIBRES OPTIQUES. LE PREMIER CHAPITRE PORTE SUR LA PRESENTATION DES PROPRIETES FONDAMENTALES DES STRUCTURES A PUITS QUANTIQUES CONTRAINTS. IL COMPORTE UNE DESCRIPTION REALISTE DE LA STRUCTURE DE BANDES OBTENUE PAR RESOLUTION DE L'HAMILTONIEN DE PIKUS-BIR. IL PRESENTE ENSUITE LE CALCUL DES SPECTRES DE GAIN, DE GAIN DIFFERENTIEL, ET DE FACTEUR D'ELARGISSEMENT DE RAIE AINSI QUE CELUI DES DIFFERENTES COMPOSANTES RADIATIVE ET NON RADIATIVES DU COURANT DE RECOMBINAISON. LE SECOND CHAPITRE CONCERNE L'APPROFONDISSEMENT DE L'ETUDE DES RECOMBINAISONS ASSISTEES PAR EFFET AUGER, PREPONDERANTES DANS LES LASERS UTILISES POUR LES TELECOMMUNICATIONS OPTIQUES. UNE MODELISATION RIGOUREUSE ET ORIGINALE DU COURANT AUGER A ETE DEVELOPPEE AFIN DE CLARIFIER LES RESULTATS EXPERIMENTAUX DE LA LITTERATURE. ELLE MET EN EVIDENCE L'INFLUENCE DE PARAMETRES CRITIQUES, TELS QUE L'EPAISSEUR DE PUITS, LE TAUX DE CONTRAINTE ET LA TEMPERATURE SUR LA DENSITE DE COURANT AUGER. LE LOGICIEL DE SIMULATION CADILAC (CONCEPTION ASSISTEE DE DIODES LASER ET D'AMPLIFICATEURS OPTIQUES A PUITS CONTRAINTS) EST ENSUITE PRESENTE. CE LOGICIEL, QUI INTEGRE UNE DESCRIPTION APPROFONDIE DES PHENOMENES QUANTIQUES ET DE CONTRAINTES, COUPLEE AU CALCUL DES MODES OPTIQUES GUIDES, PERMET DE DEDUIRE LES PERFORMANCES A PARTIR DES PARAMETRES CLES D'UN COMPOSANT (PARAMETRES STRUCTURAUX, TEMPERATURE, CONDITIONS DE POLARISATION, ETC.). LE DERNIER CHAPITRE COMPARE LE COMPORTEMENT THEORIQUE ET EXPERIMENTAL DE DEUX SERIES DE LASERS EMETTANT A 1,55 M, PRESENTANT DES COUCHES ACTIVES L'UNE CONTRAINTE EN COMPRESSION, L'AUTRE A CONTRAINTE COMPENSEE. LA BONNE ADEQUATION THEORIE/EXPERIENCE PERMET DE VALIDER LE BIEN FONDE DES MODELES THEORIQUES ET DE DEDUIRE UNE METHODOLOGIE D'ANALYSE DE DIODES LASER, OUVRANT AINSI UNE VOIE ORIGINALE ET FACILE A METTRE EN UVRE POUR DETERMINER DES PARAMETRES CLES D'UN COMPOSANT.
Download or read book DIODES LASER A PUITS QUANTIQUE written by Béatrice Saint-Cricq and published by . This book was released on 1987 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: LE TRAITEMENT THEORIQUE DES MECANISMES D'EMISSION DANS LES PUITS QUANTIQUES S'APPUIE SUR UN MODELE ORIGINAL POUR LES REGLES DE SELECTION LORS DE LA TRANSITION. SUR CETTE BASE, LA METHODOLOGIE DE CALCUL DU GAIN OPTIQUE ET DES CARACTERISTIQUES GAIN-COURANT EST PRESENTEE ET EST COMPLETEE PAR L'ANALYSE DES PROPRIETES DE PROPAGATION ET DE LA CONDITION D'OSCILLATION LASER. UNE METHODOLOGIE GLOBALE DE DETERMINATION DE LA DENSITE DE COURANT DE SEUIL EST PRESENTEE ET LES REGLES D'OPTIMISATION DES DISPOSITIFS SONT DISCUTEES. EN CE QUI CONCERNE LA REALISATION DES DIODES LASER, LES PARAMETRES TECHNOLOGIQUES LES PLUS SENSIBLES SONT ETUDIES ET LA PROCEDURE D'ELABORATION DEFINIE POUR LA CROISSANCE DES PUITS QUANTIQUES
Download or read book Contribution l optimisation de structures laser puits quantiques contraints sur la maille d InP written by Bernard Calvas and published by . This book was released on 1994 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE MEMOIRE PRESENTE L'ETUDE THEORIQUE ET EXPERIMENTALE DE LA STRUCTURE DE BANDE ET DES PERFORMANCES LASERS DES HETEROSTRUCTURES SEMI-CONDUCTRICES A PUITS QUANTIQUES A BASE DE GAINAS OU DE GAINASP CONTRAINTS SUR INP. DANS LA PREMIERE PARTIE, LES DEFINITIONS ELEMENTAIRES CONCERNANT LE SCHEMA DE BANDE ET LE MODELE DE LA FONCTION ENVELOPPE SONT RAPPELEES. LA DEUXIEME PARTIE EXPOSE LES MODELES THEORIQUES PERMETTANT DE CALCULER LES COURBES DE DISPERSION DANS LE PLAN DES COUCHES D'UN PUITS CONTRAINT ET LES SPECTRES DE GAIN OPTIQUE EN FONCTION DE L'INJECTION. L'EXPERIENCE DE SPECTROSCOPIE DE PHOTOCONDUCTIVITE EST DECRITE DANS LA TROISIEME PARTIE. LA QUATRIEME PARTIE EST UNE PRESENTATION DES TRAVAUX REALISES SUR DES SYSTEMES A PUITS QUANTIQUES EN TERNAIRE GAINAS ET EN QUATERNAIRE GAINASP CONTRAINTS EN COMPRESSION SUR LA MAILLE D'INP. LES PERFORMANCES DE CES DEUX TYPES DE STRUCTURE SONT COMPAREES ET LEUR APPLICATION A LA CONSTRUCTION DE LASERS A 1.55M EST ENVISAGEE. LE SYSTEME A PUITS TERNAIRE GAINAS CONTRAINT EN EXTENSION SUR LA MAILLE D'INP EST ANALYSE DANS LA CINQUIEME PARTIE. LES LASERS CONSTRUITS SUR CE SYSTEME PRESENTENT UN COURANT DE SEUIL BAS ET UN RENDEMENT ELEVE SURPRENANTS POUR DES STRUCTURES EN PRINCIPE DE TYPE II. CE COMPORTEMENT EST INTERPRETE. LA SIXIEME PARTIE EST CONSACREE A L'ETUDE DES EFFETS DU CHAMP ELECTRIQUE SUR LES HETEROJONCTIONS DE TYPE PIN A PUITS QUANTIQUES CONTRAINTS INDEPENDANTS OU COUPLES. ENFIN, LA CONCLUSION RAPPELLE LES PRINCIPAUX RESULTATS OBTENUS ET DONNE UNE IDEE DE L'ORIENTATION DES RECHERCHES A MENER DANS LE DOMAINE
Download or read book tude physique de diodes laser de puissance written by Julien Le Clec'h and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les contraintes induites au sein des diodes laser à bas de GaAs, mono-modes, fortes puissances, de pompe émettant à 980 nm sont étudiées, afin d'en comprendre les origines, et de les maîtriser lors des étapes du procédé de fabrication des modules laser. Nous nous intéressons ici, aux contraintes induites lors de l'opération de brasure des diodes laser sur leur embase. En effet, il apparaît que la nature de l'embase, l'outil « pick-and-place », et les conditions ther- miques du cycle de brasure jouent un rôle déterminant dans l'obtention de composants performants, et fiables, au travers de la maîtrise des contraintes induites. Ainsi, nous montrons qu'il est possible de concevoir une embase bi-matériaux générant un faible niveau de contrainte dans la diode laser, tout en préservant les caractéristiques thermiques et élec- triques. Nous discutons aussi de la déformée, et donc des contraintes appliquées à la diode laser par l'outil « pick-and-place » en fonction de son état de surface, et montrons la relation entre profil de la diode et qualité de la brasure. Enfin, nous abordons aussi l'aspect paramètres de brasure à travers des suites ordonnées d'essais, mettant ainsi en évidence les conditions optimum à choisir en terme de temps et température de cycle de brasure, de force appliquée sur la diode laser, et de la structure métallique verticale de l'embase.
Download or read book Organic Solid State Lasers written by Sébastien Forget and published by Springer. This book was released on 2013-07-03 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.
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 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 Laser 50 Years Of Discoveries written by Fabien Bretenaker and published by World Scientific. This book was released on 2014-10-27 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique book provides an overview of the principle and applications of lasers enriched with numerous illustrations.Being over fifty years old, lasers continue to amaze us. Their performance characteristics are constantly reaching new limits, and the scope of their applications continues to expand. Yet, it took years of effort by teams of physicists to transform the fundamental notions of Einstein into the first experimental beam of laser light. And history is still going on as fundamental research is now triggered by its remarkable properties.This book addresses every aspects of laser light, from its fundamental principles to its industrial applications, at a level particularly suited for high school teachers, students, and anybody curious about science and technology.
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 Physical Properties of Amorphous Materials written by David Adler and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute for Amorphous Studies was founded in 1982 as the international center for the investigation of amorphous mate rials. It has since played an important role in promoting the und er standing of disordered matter in general. An Institute lecture series on "Fundamentals of Amorphous Materials and Devices" was held during 1982-83 with distinguished speakers from universities and industry. These events were free and open to the public ,and were attended by many representatives of the scientific community. The lectures themselves were highly successful inasmuch as they provided not only formal instruction but also an opportunity for vigorous and stimulating debate. That last element could not be captured within the pages of a book I but the lectures concentrated on the latest advances in the field I which is why their essential contents are he re reproduced in collective form. Together they constitute an interdisciplinary status report of the field. The speakers brought many different viewpoints and a variety of back ground experiences io bear on the problems involved I but though language and conventions vary I the essential unity of the concerns is very clear I as indeed are the ultimate benefits of the many-sided approach.
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 Coherent Optical Processing written by Henry J. Caulfield and published by . This book was released on 1975 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Cognitive Radio Systems written by Wei Wang and published by . This book was released on 2009 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cognitive radio is a hot research area for future wireless communications in the recent years. In order to increase the spectrum utilization, cognitive radio makes it possible for unlicensed users to access the spectrum unoccupied by licensed users. Cognitive radio let the equipments more intelligent to communicate with each other in a spectrum-aware manner and provide a new approach for the co-existence of multiple wireless systems. The goal of this book is to provide highlights of the current research topics in the field of cognitive radio systems. The book consists of 17 chapters, addressing various problems in cognitive radio systems.
