DYNAMIQUE DU COUPLAGE DES DIFFUSIONS BRILLOUIN LONGITUDINALE ET TRANSVERSE DANS LES LASERS A FIBRE OPTIQUE PDF Download
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Author: ISABELLE.. BONGRAND
Publisher:
ISBN:
Category :
Languages : fr
Pages : 200
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Book Description
LA PRISE EN COMPTE DE L'OUVERTURE NUMERIQUE FINIE DES FIBRES OPTIQUES UNIMODALES NOUS PERMET DE DISTINGUER LA RETRODIFFUSION BRILLOUIN STIMULEE (DBS) ET LA DIFFUSION BRILLOUIN DE GAINE (DBG), MOINS CONNUE, QUI SONT RESPECTIVEMENT L'INTERACTION DE LA LUMIERE AVEC DES ONDES ACOUSTIQUES AXIALE DE TRES HAUTE FREQUENCE (34 GHZ) ET TRANSVERSE (5-1000 MHZ) ; NOUS EN ETABLISSONS LES MODELES COHERENTS A TROIS ONDES (POMPE-BRILLOUIN-ACOUSTIQUE). UNE SECONDE PARTIE, ESSENTIELLEMENT EXPERIMENTALE, EN DECRIT LA DYNAMIQUE NON LINEAIRE, EN BON ACCORD QUALITATIF ET QUANTITATIF AVEC LES SIMULATIONS NUMERIQUES. LA STABILITE DES LASERS BRILLOUIN (DBS) APPARAIT LIMITEE PAR LEUR LONGUEUR. DES INSTABILITES LIEES A LA DBG INTERVIENNENT POUR LES RESONATEURS A TRES LONGUES FIBRES OPTIQUES, QUE NOUS UTILISONS POUR METTRE EN EVIDENCE UNE MODULATION CROISEE D'AMPLITUDE. NOUS ETUDIONS ENSUITE LE COUPLAGE DES DEUX MECANISMES, ET LA DYNAMIQUE NON LINEAIRE A QUATRE ONDES ASSOCIEE EN TENANT COMPTE D'UNE SEULE RESONANCE ACOUSTIQUE TRANSVERSE. DE NOUVEAUX REGIMES COMPLEXES SONT OBTENUS, COMME DES IMPULSIONS BRILLOUIN TRES LARGES (200 NS) FORTEMENT MODULEES AUX FREQUENCES DBG. ON S'INTERESSE TOUT PARTICULIEREMENT A L'ELARGISSEMENT ET A LA COMPRESSION D'IMPULSIONS NON MODULEES. BIEN QUE LA DBG SOIT A PRIORI PERTURBATIVE, ON OBSERVE DANS CERTAINS CAS DES STRUCTURES QUASI-SOLITONIQUES ETROITES (18 NS), COMPRIMEES D'UN FACTEUR 2 PAR RAPPORT A CELLES OBSERVEES DANS DES LASERS BRILLOUIN A FIBRE COURTE. UNE ETUDE NUMERIQUE SYSTEMATIQUE MONTRE QUE LE PARAMETRE DE CONTROLE DE CE NOUVEAU MECANISME EST LE RAPPORT ENTRE L'INTERVALLE SPECTRAL LIBRE DE LA CAVITE ET LA FREQUENCE DBG EN CAUSE. ENFIN, UNE QUATRIEME PARTIE ABORDE L'ETUDE DU PROBLEME A N ONDES (TOUS LES MODES ACOUSTIQUES TRANSVERSES PARTICIPANT) ET MET EN EVIDENCE L'IMPORTANCE DE MODES ACOUSTIQUES SE PROPAGEANT DANS LE MANTEAU MECANIQUE DE LA FIBRE, AVANT DE TIRER LES CONSEQUENCES DE CETTE ETUDE POUR LES APPLICATIONS DE TYPE TELECOMMUNICATIONS.
Author: ISABELLE.. BONGRAND
Publisher:
ISBN:
Category :
Languages : fr
Pages : 200
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Book Description
LA PRISE EN COMPTE DE L'OUVERTURE NUMERIQUE FINIE DES FIBRES OPTIQUES UNIMODALES NOUS PERMET DE DISTINGUER LA RETRODIFFUSION BRILLOUIN STIMULEE (DBS) ET LA DIFFUSION BRILLOUIN DE GAINE (DBG), MOINS CONNUE, QUI SONT RESPECTIVEMENT L'INTERACTION DE LA LUMIERE AVEC DES ONDES ACOUSTIQUES AXIALE DE TRES HAUTE FREQUENCE (34 GHZ) ET TRANSVERSE (5-1000 MHZ) ; NOUS EN ETABLISSONS LES MODELES COHERENTS A TROIS ONDES (POMPE-BRILLOUIN-ACOUSTIQUE). UNE SECONDE PARTIE, ESSENTIELLEMENT EXPERIMENTALE, EN DECRIT LA DYNAMIQUE NON LINEAIRE, EN BON ACCORD QUALITATIF ET QUANTITATIF AVEC LES SIMULATIONS NUMERIQUES. LA STABILITE DES LASERS BRILLOUIN (DBS) APPARAIT LIMITEE PAR LEUR LONGUEUR. DES INSTABILITES LIEES A LA DBG INTERVIENNENT POUR LES RESONATEURS A TRES LONGUES FIBRES OPTIQUES, QUE NOUS UTILISONS POUR METTRE EN EVIDENCE UNE MODULATION CROISEE D'AMPLITUDE. NOUS ETUDIONS ENSUITE LE COUPLAGE DES DEUX MECANISMES, ET LA DYNAMIQUE NON LINEAIRE A QUATRE ONDES ASSOCIEE EN TENANT COMPTE D'UNE SEULE RESONANCE ACOUSTIQUE TRANSVERSE. DE NOUVEAUX REGIMES COMPLEXES SONT OBTENUS, COMME DES IMPULSIONS BRILLOUIN TRES LARGES (200 NS) FORTEMENT MODULEES AUX FREQUENCES DBG. ON S'INTERESSE TOUT PARTICULIEREMENT A L'ELARGISSEMENT ET A LA COMPRESSION D'IMPULSIONS NON MODULEES. BIEN QUE LA DBG SOIT A PRIORI PERTURBATIVE, ON OBSERVE DANS CERTAINS CAS DES STRUCTURES QUASI-SOLITONIQUES ETROITES (18 NS), COMPRIMEES D'UN FACTEUR 2 PAR RAPPORT A CELLES OBSERVEES DANS DES LASERS BRILLOUIN A FIBRE COURTE. UNE ETUDE NUMERIQUE SYSTEMATIQUE MONTRE QUE LE PARAMETRE DE CONTROLE DE CE NOUVEAU MECANISME EST LE RAPPORT ENTRE L'INTERVALLE SPECTRAL LIBRE DE LA CAVITE ET LA FREQUENCE DBG EN CAUSE. ENFIN, UNE QUATRIEME PARTIE ABORDE L'ETUDE DU PROBLEME A N ONDES (TOUS LES MODES ACOUSTIQUES TRANSVERSES PARTICIPANT) ET MET EN EVIDENCE L'IMPORTANCE DE MODES ACOUSTIQUES SE PROPAGEANT DANS LE MANTEAU MECANIQUE DE LA FIBRE, AVANT DE TIRER LES CONSEQUENCES DE CETTE ETUDE POUR LES APPLICATIONS DE TYPE TELECOMMUNICATIONS.
Author: DERRADJI.. BAHLOUL
Publisher:
ISBN:
Category :
Languages : fr
Pages : 156
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Book Description
CE MEMOIRE PRESENTE UNE ETUDE ESSENTIELLEMENT EXPERIMENTALE DES LASERS BRILLOUIN A FIBRE OPTIQUE UNIMODALE. LA PREMIERE PARTIE PRECISE QUANTITATIVEMENT LES CARACTERISTIQUES DE LA DIFFUSION BRILLOUIN STIMULEE (DBS) DANS LES FIBRES CONSIDEREE COMME UNE INTERACTION NON LINEAIRE RESONNANTE A TROIS ONDES. LE DOPAGE QUI CONFERE A LA FIBRE SA STRUCTURE GUIDANTE MODIFIE AUSSI LOCALEMENT LA CONDITION DE RESONANCE. IL CONVIENT DONC DE DEFINIR UNE AIRE EFFECTIVE SPECIFIQUE PRENANT EN COMPTE LA STRUCTURE TRANSVERSE DE LA FIBRE, CE QUI MENE A UNE NOUVELLE METHODE POUR ELEVER LE SEUIL BRILLOUIN DANS LES FIBRES. UNE NOUVELLE TECHNIQUE DE MESURE DU GAIN BRILLOUIN PRESENTE L'AVANTAGE DE FONCTIONNER EN DEHORS DU REGIME PARAMETRIQUE ; ELLE NECESSITE UNE SEULE SOURCE LASER ET UTILISE EN SON PRINCIPE LES REFLEXIONS SUR LES EXTREMITES DE FIBRE. LA DEUXIEME PARTIE DU MEMOIRE CONCERNE LES SOURCES : LES LASERS BRILLOUIN SONT CONNUS POUR LEUR COHERENCE. NOUS AVONS PU REALISER UN LASER BRILLOUIN A LONGUEUR D'ONDE DE 1,319 M FONCTIONNANT AUSSI BIEN EN REGIME IMPULSIONNEL QUE CONTINU. ON VALIDE AINSI EXPERIMENTALEMENT DANS L'INFRAROUGE LES PREDICTIONS THEORIQUES ET NUMERIQUES DU MODELE COHERENT A TROIS ONDES, NOTAMMENT LA BIFURCATION DU REGIME MIROIR VERS LE REGIME IMPULSIONNEL. L'UTILISATION D'UN CIRCULATEUR OPTIQUE A PERMIS LA SIMPLIFICATION DU MONTAGE ET DE L'EMPLOI DU LASER BRILLOUIN EN ANNEAU "TOUT FIBRE". A L'AIDE DE DISPOSITIFS INTEGRES NOUS AVONS OBTENU UN BON ACCORD QUALITATIF ET QUANTITATIF POUR LA PREMIERE FOIS ENTRE LA THEORIE ET L'EXPERIENCE. LES IMPULSIONS SOLITONIQUES OBSERVEES PEUVENT ETRE SUB- OU SUPRALUMINIQUE ET PRESENTENT UNE DISSYMETRIE QUI AUGMENTE AVEC LA FINESSE DE LA CAVITE. ON RETROUVE EXPERIMENTALEMENT LE LIEN RECEMMENT ETABLIE ANALYTIQUEMENT ENTRE LA VITESSE DE L'IMPULSION ET LA PENTE DE SON FRONT AVANT. POUR LES GRANDES FINESSES, SEULS LES REGIMES IMPULSIONNEL ET CONTINU SONT STABLES, LE REGIME OSCILLATOIRE N'EST QU'UN TRANSITOIRE PLUS OU MOINS LENT.
Author: Ahmed Belasri
Publisher: Springer Nature
ISBN: 9811554447
Category : Technology & Engineering
Languages : en
Pages : 659
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Book Description
This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.
Author: Joseph Weber
Publisher: Courier Corporation
ISBN: 0486438872
Category : Science
Languages : en
Pages : 210
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Book Description
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.
Author: Stefano Boccaletti
Publisher: A I P Press
ISBN:
Category : Mathematics
Languages : en
Pages : 384
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Book Description
The 8th Experimental Chaos Conference again demonstrated the broad spectrum of areas where nonlinear dynamics plays an important role, such as circuits, hydrodynamics, optics, chemistry, fracture dynamics, neuroscience, and cognitive science. Additional contributions outline the trends for development and application of concepts and techniques of nonlinear dynamics.
Author: Mária Németh Lenke
Publisher:
ISBN:
Category : American drama
Languages : en
Pages : 164
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Book Description
Author: Jean Daillant
Publisher: Springer Science & Business Media
ISBN: 3540486968
Category : Science
Languages : en
Pages : 347
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Book Description
The reflection of and neutrons from surfaces has existed as an x-rays exp- imental for almost it is in the last technique fifty Nevertheless, only years. decade that these methods have become as of enormously popular probes This the surfaces and interfaces. to be due to of several appears convergence of intense different circumstances. These include the more n- availability be measured orders tron and sources that can over (so reflectivity x-ray many of and the much weaker surface diffuse can now also be magnitude scattering of thin films and studied in some the detail); growing importance multil- basic the realization of the ers in both and technology research; important which in the of surfaces and and role roughness plays properties interfaces; the of statistical models to characterize the of finally development topology its and its characterization from on roughness, dependence growth processes The of and to surface scattering experiments. ability x-rays neutro4s study four five orders of in scale of surfaces over to magnitude length regardless their and also their to ability probe environment, temperature, pressure, etc. , makes these the choice for buried interfaces often probes preferred obtaining information about the microstructure of often in statistical a global surfaces, the local This is manner to complementary imaging microscopy techniques, of such studies in the literature witnessed the veritable by explosion published the last few Thus these lectures will useful for over a resource years.
Author: M.O. Manasreh
Publisher: Elsevier
ISBN: 0080534449
Category : Science
Languages : en
Pages : 463
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Book Description
Research advances in III-nitride semiconductor materials and device have led to an exponential increase in activity directed towards electronic and optoelectronic applications. There is also great scientific interest in this class of materials because they appear to form the first semiconductor system in which extended defects do not severely affect the optical properties of devices. The volume consists of chapters written by a number of leading researchers in nitride materials and device technology with the emphasis on the dopants incorporations, impurities identifications, defects engineering, defects characterization, ion implantation, irradiation-induced defects, residual stress, structural defects and phonon confinement. This unique volume provides a comprehensive review and introduction of defects and structural properties of GaN and related compounds for newcomers to the field and stimulus to further advances for experienced researchers. Given the current level of interest and research activity directed towards nitride materials and devices, the publication of the volume is particularly timely. Early pioneering work by Pankove and co-workers in the 1970s yielded a metal-insulator-semiconductor GaN light-emitting diode (LED), but the difficulty of producing p-type GaN precluded much further effort. The current level of activity in nitride semiconductors was inspired largely by the results of Akasaki and co-workers and of Nakamura and co-workers in the late 1980s and early 1990s in the development of p-type doping in GaN and the demonstration of nitride-based LEDs at visible wavelengths. These advances were followed by the successful fabrication and commercialization of nitride blue laser diodes by Nakamura et al at Nichia. The chapters contained in this volume constitutes a mere sampling of the broad range of research on nitride semiconductor materials and defect issues currently being pursued in academic, government, and industrial laboratories worldwide.
Author: Paolo Mele
Publisher:
ISBN: 9781536160864
Category : Zinc oxide thin films
Languages : en
Pages : 0
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Book Description
Zinc oxide (ZnO) is an n-type semiconductor with versatile applications such as optical devices in ultraviolet region, piezoelectric transducers, transparent electrode for solar cells and gas sensors. This book "ZnO Thin Films: Properties, Performance and Applications" gives a deep insight in the intriguing science of zinc oxide thin films. It is devoted to cover the most recent advances and reviews the state of the art of ZnO thin films applications involving energy harvesting, microelectronics, magnetic devices, photocatalysis, photovoltaics, optics, thermoelectricity, piezoelectricity, electrochemistry, temperature sensing. It serves as a fundamental information source on the techniques and methodologies involved in zinc oxide thin films growth, characterization, post-deposition plasma treatments and device processing. This book will be invaluable to the experts to consolidate their knowledge and provide insight and inspiration to beginners wishing to learn about zinc oxide thin films.
Author: Razvan Gurau
Publisher: Oxford University Press
ISBN: 0198787936
Category : Mathematics
Languages : en
Pages : 345
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Book Description
This book introduces "Random Tensors," a framework for studying random geometries in any dimension. It provides a complete derivation of the key results in the field. Whatever form a theory of Quantum Gravity may take, it must incorporate random geometry.
