Download or read book MODELISATION ET CARACTERISATION DE LA REPONSE FM DES LASERS A CONTRE REACTION DISTRIBUEE MONO ET MULTI SECTION written by Douglas Baney and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: LE COUPLAGE PHASE-AMPLITUDE DANS LA CAVITE DES LASERS SEMI-CONDUCTEURS AUTORISE LA MODULATION DIRECTE DE LA FREQUENCE OPTIQUE PAR COMMANDE DU COURANT INJECTE. L'APPARITION DES LASERS MULTI-SECTIONS PERMET UNE AUGMENTATION CONSIDERABLE DE L'EFFICACITE, L'OBTENTION D'UNE REPONSE PLATE ET D'UNE RELATION DE PHASE CONSTANTE ENTRE LA MODULATION DE LA FREQUENCE OBTENUE ET LES VARIATIONS DU COURANT D'INJECTION. CE MEMOIRE PRESENTE UNE ETUDE THEORIQUE ET EXPERIMENTALE DES CARCTERISTIQUES DYNAMIQUES DES LASERS A CONTRE-REACTION DISTRIBUEE DE TYPES MONO ET MULTI-SECTIONS. UNE ATTENTION PARTICULIERE EST PORTEE A LA MODULATION EN FREQUENCE DE CES STRUCTURES ET AUX TECHNIQUES SPECTROSCOPIQUES INDISPENSABLES A LA CARACTERISATION DE LEURS PROPRIETES SPECTRALES. DES TECHNIQUES SPECTROSCOPIQUES A HAUTE RESOLUTION SONT PROPOSEES ET DEVELOPPEES AFIN DE PERMETTRE LA MESURE DE LA DENSITE SPECTRALE DU CHAMP OPTIQUE ET, POUR DES SIGNAUX A FORT INDICE DE MODULATION LA MESURE DE L'EXCURSION DYNAMIQUE DE LA FREQUENCE OPTIQUE. POUR LES LASERS MONO-SECTION, IL EST TOUT D'ABORD MONTRE QUE LES NON-LINEARITES SONT DES PHENOMENES DETERMINANTS POUR LA REPONSE FM. IL S'AVERE EN PARTICULIER QUE LA COMPRESSION DE GAIN JOUE UN ROLE ESSENTIEL POUR L'OBTENTION D'UNE PHASE DE LA REPONSE FM CONSTANTE, POUR DES FREQUENCES DE MODULATION SUPERIEURES A LA FREQUENCE DE COUPURE DE L'EFFET THERMIQUE ET INFERIEURES A LA FREQUENCE DE RELAXATION. IL EST EGALEMENT MONTRE QUE LES EFFETS DE COMPRESSION DE GAIN ET DE COURBURE DE CE DERNIER PEUVENT ETRE PRIS EN COMPTE PAR UN FACTEUR DE COUPLAGE PHASE-AMPLITUDE EFFECTIF. UNE THEORIE SIMPLE EST ENSUITE PROPOSEE POUR MODELISER LA REPONSE FM DES LASERS MULTI-SECTIONS. LA REPARTITION DES PHOTONS DANS LA CAVITE LASER ET LES INHOMOGENEITES, STRUCTURELLES OU INDUITES, ENTRE LES DIFFERENTES SECTIONS DE LA CAVITE LASER, JOUENT UN ROLE IMPORTANT DANS LA CARACTERISTIQUE DE MODULATION DE CES LASERS. DES MESURES DE LA.
Download or read book MODELISATIONS ET CARACTERISATION DE LASERS A SEMI CONDUCTEURS MONOFREQUENCES CONTINUMENT ACCORDABLES EN LONGUEUR D ONDE written by PASCAL.. CORREC and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: L'OBJET DE CETTE THESE EST LA MODELISATION ET LA CARACTERISTION DE LASERS A SEMICONDUCTEURS MONOFREQUENCES CONTINUMENT ACCORDABLES EN LONGUEUR D'ONDE. DE TELS LASERS SONT INDISPENSABLES AU DEVELOPPEMENT DES SYSTEMES DE TRANSMISSION COHERENTS. APRES AVOIR RAPPELE LE FONCTIONNEMENT D'UN LASER SEMICONDUCTEUR ET LE PRINCIPE DU LASER A CONTRE-REACTION DISTRIBUEE (DFB), NOUS ETABLISSONS LES EQUATIONS DES MODES COUPLES QUI TIENNENT COMPTE DE LA POSITION DES FACES PAR RAPPORT AU RESEAU ET DONNENT L'EXPRESSION DU COEFFICIENT DE COUPLAGE K. NOUS UTILISONS UNE METHODE MATRICIELLE POUR LES RESOUDRE ET ETUDIONS SUCCESSIVMEENT LE REFLECTEUR DE BRAGG, LE LASER DFB DROIT ET DES LASERS DEPHASES. NOUS COMPLETONS NOTRE ANALYSE EN Y INCLUANT LE PHENOMENE DE DEPLETION AXIALE DE PORTEURS (HOLE BURNING) ET APPLIQUONS NOTRE MODELE A L'ETUDE DE LA STABILITE DES LASERS DEPHASES MONO-ELECTRODES ET DE L'ACCORDABILITE DES COMPOSANTS MULTI-ELECTRODES: LASER A RESEAU DEPHASE, LASER CNET A DEPHASEUR PASSIF OU ACTIF, LASER DROIT. POUR CHAQUE STRUCTURE, NOUS DETERMINONS LA LONGUEUR D'ONDE D'EMISSION ET LA PUISSANCE EMISE EN FONCTION DES COURANTS INJECTES. NOUS AVONS MIS AU POINT LA DECOUPE DE L'ELECTRODE SUPERIEURE EN ASSOCIANT UN USINAGE IONIQUE ET UNE LEGERE ATTAQUE CHIMIQUE ET DEVELOPPE UN BANC DE CARACTERISATION DE LASERS MULTI-ELECTRODES PERMETTANT DE LES EVALUER RAPIDEMENT ET DE FACON CONVIVIALE. NOUS AVONS TESTE DE NOMBREUX COMPOSANTS MONO- ET MULTI-ELECTRODES ET AVONS OBSERVE EXPERIMENTALEMENT DES COMPORTEMENTS EN ACCORD AVEC LES PREDICTIONS THEORIQUES, TANT POUR LES LASERS DROITS QUE POUR LES LASERS A DEPHASEUR. PLUSIEURS LASERS ONT ETE UTILISES AVEC SUCCES DANS DES LIAISONS EXPERIMENTALES
Download or read book From design to characterization of III V on silicon lasers for photonic integrated circuits written by Hélène Duprez and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ces trois années de thèse balayent la conception, la fabrication et la caractérisation de lasers III V sur silicium à 1.31 μm pour les data-communications. Le design des sources englobe notamment l'optimisation du couplage entre l'empilement III V et le silicium, effectué grâce à un taper adiabatique, ainsi que l'étude de la cavité laser inscrite, comme le taper, dans le silicium. Trois types de cavités à base de réseaux ont été étudiées: les cavités à contre-réaction distribuée (DFB pour distributed feedback), celles à réseaux de Bragg distribuées (DBR pour distributed Bragg reflector) et enfin celles à réseaux de Bragg échantillonnées (SGDBR pour sampled-grating DBR). Deux solutions ont été abordées concernant les lasers DFB: le réseau, inscrit dans le guide silicium sous la zone de gain, est soit gravé au-dessus du guide Si, soit sur les côtés. La seconde possibilité, appelée 'DFB lasers couplés latéralement', simplifie la fabrication et élargit les possibilités de design.Les lasers DFB fabriqués sont très prometteurs en terme de puissance (avec jusque 20 mW dans le guide) ainsi que pour leur pureté spectrale (avec une différence de plus de 50 dB entre le mode principal et le mode suivant). Une accordabilité spectrale de plus de 27 nm a été obtenue en continu avec les lasers SGDBR tout en conservant une très bonne pureté spectrale et une puissance de plus de 7 mW dans le guide.
Download or read book Etude des non lin arit s dans les lasers contre r action distribu e written by Hans Bissessur and published by . This book was released on 1994 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: LE DEVELOPPEMENT DE LASERS A SEMI-CONDUCTEURS EMETTANT UNE PUISSANCE ELEVEE AVEC UN BON TAUX DE REJECTION DES MODES SECONDAIRES, ET PERFORMANTS DU POINT DE VUE DE LA REPONSE A UNE MODULATION OU DE LA LARGEUR DE RAIE EXIGE LA PRISE EN COMPTE DETAILLEE DU COUPLAGE PHOTONS-PORTEURS DANS LA CAVITE LASER. EN EFFET, LES DENSITES DE PHOTONS ET DE PORTEURS SONT GENERALEMENT INHOMOGENES LE LONG DE L'AXE DE PROPAGATION. NOUS PRESENTONS UN MODELE DETAILLE A BASE DE MATRICES DE TRANSFERT PERMETTANT DE CALCULER LA PUISSANCE ET LA LONGUEUR D'ONDE D'EMISSION, LE TAUX DE REJECTION DES MODES SECONDAIRES, AINSI QUE LES REPONSES DYNAMIQUES ET LA LARGEUR DE RAIE D'UN LASER DFB QUELCONQUE. NOUS MONTRONS QUE LES INHOMOGENEITES LIMITENT LA PLAGE DE FONCTIONNEMENT MONOMODE DU COMPOSANT ET INTRODUISENT DES NON-LINEARITES DANS LE COMPORTEMENT EN PUISSANCE ET EN LARGEUR DE RAIE. DES STRUCTURES A DEPHASAGES MULTIPLES SONT PROPOSEES POUR RELACHER LES CONTRAINTES SUR LE COEFFICIENT DE COUPLAGE, ET COMPAREES AUX STRUCTURES CLASSIQUES SANS DEPHASAGE OU AVEC UN DEPHASAGE UNIQUE D'UN QUART D'ONDE. L'ETUDE EXPERIMENTALE CONFIRME L'INTERET DES FAIBLES COEFFICIENTS DE COUPLAGE OU LE TRAITEMENT ANTI-REFLETS DE LA FACE DE SORTIE POUR L'OBTENTION DE BONS RENDEMENT SUR PLAQUE, AINSI QUE LA FORTE DEPENDANCE DE LA LARGEUR DE RAIE AVEC LA LONGUEUR DE CAVITE. L'ACCORDABILITE DES LASERS A ELECTRODES MULTIPLES EST ENSUITE ETUDIEE EN FONCTION DES COURANTS APPLIQUES. LES EFFETS THERMIQUES SONT INCLUS DANS LA MODELISATION. DIFFERENTES CONFIGURATIONS SONT EXAMINEES EN VUE D'OBTENIR UNE REPONSE FM (RESP. AM) IMPORTANTE ET PLATE A FAIBLE FREQUENCE. ENFIN, LA REPONSE EN GRANDS SIGNAUX EST MODELISEE, AVEC LES DIFFERENTS PARAMETRES PERMETTANT DE L'AMELIORER. L'INCLUSION DE LA COURBE DE GAIN EXACTE EST GENERALEMENT NECESSAIRE POUR UNE OPTIMISATION FINE DU COMPOSANT.
Download or read book High Resolution Stratigraphy written by E. A. Hailwood and published by Geological Society Publishing House. This book was released on 1993 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radioactive Aerosols written by Constantin Papastefanou and published by Elsevier. This book was released on 2011-07-28 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whenever radioactivity is released to the atmosphere, for example by the detonation of nuclear weapons or the testing of nuclear weapons or from nuclear reactor accidents that fraction of it which remains airborne for more than a few hours is liable to be attached to aerosol particles. The resulting radioactive aerosols are carried by atmospheric mixing processes until they settle out or are scavenged by precipitation. The radiation exposure pathway of maximum concern to humans is by inhalation of aerosols and their deposition in the respiratory tract. In this context, it is important to note that radioactive aerosols are commonly of natural origin alos. In particular, the associated radionuclides can be of natural terrestrial origin, such as the decay products of radon gas, or they can e cosmogenic, such as beryllium-7. The exposure of miners of uranium and other ores and minerals to radon and its aerosol-borne decay products is of major significance. The book describes the formation of aerosols, their aerodynamic size distribution, their atmospheric residence time, their sampling and measurement, the range of radioactive aerosols found and studied thus far, including man-made nuclides and radon decay products and their interaction with man, including deposition in the lung and subsequent health effects. - Advanced level science handbook for researchers, scientists and academics - Covers all aspects of radiation exposure in humans, including subsequent health implications - Presents the latest findings and analysis in this highly topical area
Download or read book Proof Theory and Automated Deduction written by Jean Goubault-Larrecq and published by Springer Science & Business Media. This book was released on 2001-11-30 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in computer applications has led to a new attitude to applied logic in which researchers tailor a logic in the same way they define a computer language. In response to this attitude, this text for undergraduate and graduate students discusses major algorithmic methodologies, and tableaux and resolution methods. The authors focus on first-order logic, the use of proof theory, and the computer application of automated searches for proofs of mathematical propositions. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book Mechanical Vibration written by William John Palm and published by . This book was released on 2007 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model, analyze, and solve vibration problems, using modern computer tools. Featuring clear explanations, worked examples, applications, and modern computer tools, William Palm's Mechanical Vibration provides a firm foundation in vibratory systems. You'll learn how to apply knowledge of mathematics and science to model and analyze systems ranging from a single degree of freedom to complex systems with two and more degrees of freedom. Separate MATLAB sections at the end of most chapters show how to use the most recent features of this standard engineering tool, in the context of solving vibration problems. The text introduces Simulink where solutions may be difficult to program in MATLAB, such as modeling Coulomb friction effects and simulating systems that contain non-linearities. Ample problems throughout the text provide opportunities to practice identifying, formulating, and solving vibration problems. KEY FEATURES Strong pedagogical approach, including chapter objectives and summaries Extensive worked examples illustrating applications Numerous realistic homework problems Up-to-date MATLAB coverage The first vibration textbook to cover Simulink Self-contained introduction to MATLAB in Appendix A Special section dealing with active vibration control in sports equipment Special sections devoted to obtaining parameter values from experimental data
Download or read book Alien Tongues written by Elizabeth Klosty Beaujour and published by . This book was released on 1989 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biological Dosimetry written by W. G. Eisert and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: In October 1982, a small international symposium was held at the Gesellschaft fUr Strahlen- und Umweltforschung mbH (GSF) in Munich as a satellite meeting of the IX International Conference on Analytical Cytology. The symposium focussed on cytometric approaches to biological dosimetry, and was, to the best of our knowledge, the first meeting on this subject ever held. There was strong encouragement from the 75 attendees and from others to publish a proceedings of the symposium. Hence this book, containing 30 of the 36 presentations, has been assembled. Dosimetry, the accurate and systematic determination of doses, usually refers to grams of substance administered or rads of ionization or some such measure of exposure of a patient, a victim or an experimental system. The term also can be used to describe the quantity of an ultimate, active agent as delivered to the appropriate target material within a biological system. Thus, for mutagens, one can speak of DNA dosimetry, meaning the number of adducts produced in the DNA of target cells such as bone-mar row stem cells or spermatogonia.
Download or read book ORTHOGRAPHY PHONOLOGY MORPHOLOGY AND MEANING written by Ram FROST and published by Lulu.com. This book was released on with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radiation Protection Activities written by United States. Environmental Protection Agency. Office of Radiation Programs and published by . This book was released on 1976 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Warming and Climate Change written by Emma Carlson Berne and published by Referencepoint Press. This book was released on 2008 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout the world, the cause and impact of global warming and climate change is being passionately debated. While many claim that a climate crisis is imminent if greenhouse gases are not curbed, others argue that the effects have been overblown. Through objective overviews, primary sources, and full-color illustrations, this title will examine What Is Global Warming and Climate Change? What Are the Consequences of Global Warming? What Are the Controversies Surrounding Global Warming? What Are the Solutions for Global Warming?
Download or read book Definiteness Effects written by Susann Fischer and published by Cambridge Scholars Publishing. This book was released on 2016-08-17 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume explores in detail the empirical and conceptual content of the definiteness effect in grammar. It brings together a variety of relevant observations from a typological, diachronic and a bilingual/second language acquisition perspective, and provides a general overview of different approaches concerned with the syntactic, morphological, semantic, and pragmatic properties of the Definiteness Effect in a series of European and non-European languages.
Download or read book Operational Radiation Safety Program written by National Council on Radiation Protection and Measurements and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Logic for Computer Science written by Jean H. Gallier and published by Courier Dover Publications. This book was released on 2015-06-18 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: This advanced text for undergraduate and graduate students introduces mathematical logic with an emphasis on proof theory and procedures for algorithmic construction of formal proofs. The self-contained treatment is also useful for computer scientists and mathematically inclined readers interested in the formalization of proofs and basics of automatic theorem proving. Topics include propositional logic and its resolution, first-order logic, Gentzen's cut elimination theorem and applications, and Gentzen's sharpened Hauptsatz and Herbrand's theorem. Additional subjects include resolution in first-order logic; SLD-resolution, logic programming, and the foundations of PROLOG; and many-sorted first-order logic. Numerous problems appear throughout the book, and two Appendixes provide practical background information.
Download or read book Ionizing Radiation written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
