Cette thèse s’inscrit dans le cadre de la montée en débit des réseaux d’accès optiques passifs. Les travaux menés durant cette thèse s’appuient sur le constat que les technologies actuelles basées sur le multiplexage temporel, arriveront à leurs limites dans les années à venir et ne pourront plus répondre à l’évolution des besoins en débit. L’étude des problèmes rencontrés lors les déploiements actuels conduit à proposer une autre forme de multiplexage plus adaptée aux débits demandés par les utilisateurs : le multiplexage fréquentiel (ou FDM/FDMA). Les travaux réalisés dans cette thèse ont pour but de montrer la faisabilité d’une telle architecture en laboratoire. Les objectifs sont de déterminer les débits atteignables, que ce soit pour le lien descendant (du central vers l’abonné) ou pour le lien montant (abonnée vers central), mais également de réaliser une étude théorique afin de mettre en lumière les limites de cette solution. Des algorithmes d’allocation dynamique de ressources ont été élaborés et validés expérimentalement afin de déterminer la capacité totale de chaque lien. L’architecture utilisant deux longueurs d’ondes distinctes (une pour le lien descendant et l’autre pour le lien montant) permet d’atteindre un débit de 40 Gbps et 20 Gbps respectivement pour le lien descendant et montant en utilisant le format de multiplexage FDM/FDMA. Enfin, une architecture hybride n’employant qu’une seule longueur d’onde pour le transport à la fois les données montantes et descendantes a été explorée et permet d’atteindre un débit symétrique de 25Gbps. / This thesis is part of the growing capacity of passive optical access networks. The works done during this thesis are based on the fact that current technologies, employing time division multiplexing, will reach their limits in the coming years and will no longer respond to changes in high bitrates requirements. The study of problems encountered during the current deployments led us to propose another form of multiplexing more suitable for bitrates requested by users: the FDM/FDMA PON, frequency division multiplexing. The work done in this thesis aim to demonstrate the feasibility of a such architecture in the laboratory. The objectives are to determine the achievable capacity, whether for the downlink (from central office to user) or the uplink (subscriber to central), but also to achieve a theoretical study to highlight the limitations of this solution. Algorithms for dynamic allocation of resources have been developed and validated experimentally to determine the total capacity of each link. The architecture using two distinct wavelengths (one for the downlink and one for the uplink) achieves a capacity of 40Gbps for the downlink and 20Gbps for the uplink by using FDM/FDMA PON. Finally, a hybrid architecture using a single wavelength to transport both uplink and downlink data has been explored and achieves a symmetrical capacity of 25Gbps

Nous avons étudié le comportement de capteurs répartis par rétrodiffusion Brillouin dans des fibres optiques soumises à des environnements radiatifs pour la mesure de contraintes thermomécaniques. Le premier chapitre présente le besoin de mesure répartie par fibre optique pour le stockage sur site géologique des déchets radioactifs de moyennes et hautes activités vie longue (MA-VL et HA-VL) envisagé par l’Andra. Le second chapitre précise la méthodologie utilisée durant la thèse. Le choix de fibres optiques utilisées ainsi que les moyens de caractérisation exploités pour étudier l’évolution de la réponse des fibres optiques y sont présentés. Dans la troisième partie, nous montrerons l’influence de l’exposition aux rayonnements UV sur le spectre Brillouin de certaines fibres optiques. La réponse de la fibre optique fortement dopées au Germanium montre une grande sensibilité de l’atténuation et des changements sur la fréquence Brillouin induits par des rayonnements UV. Dans la quatrième partie, nous montrerons les résultats de la méthodologie appliquée pour la caractérisation de la réponse capteurs répartis par rétrodiffusion Brillouin dans diverses fibres optiques au cours des irradiations gamma. Ces études ont permis de converger vers la conception d’une fibre optique spéciale dopée au Fluor qui est adaptée l’application de surveillance d’alvéole de stockage de déchets radioactifs de type HA-VL et MA-VL pendant une échelle séculaire / We studied the behavior distributed Brillouin sensor in optical fibers under radiative environments for strain and temperature measurements. The first chapter presents the need for distributed measurement by using optical fiber for the storage of radioactive waste geological site of medium and high long-lived activities (MA- VL and HA-VL) proposed by Andra. The second chapter outlines the methodology used in the thesis. The choice of fiber used and the characterization means operated to study the evolution of the response of the optical fibers are presented. In the third part, we show the influence of exposure to UV radiation on the Brillouin spectrum of several optical fibers. The response of the optical fiber highly doped with Germanium shows high sensitivity on the attenuation and the Brillouin frequency induced by UV radiation. In the fourth section, we show results from our methodology for the characterization of the response Brillouin sensors in various optical fibers during differents gamma irradiation conditions. These studies converge towards the design of a special fluorine -doped optical fiber which is suitable for the application of monitoring of the future site for the storage of radioactive waste type HA- MA- VL and VL for a century scale

L'industrie nucléaire montre un intérêt croissant pour les technologies basées sur les fibres optiques pour la transmission des données et comme capteurs. Les fibres optiques offrent plusieurs avantages et les capteurs utilisant cette technologie n'ont pas besoin d'alimentation électrique au point de détection, ils ont une réponse rapide et peuvent être facilement multiplexés : dans le cas d'un capteur de température plusieurs thermocouples peuvent être substituées par une seule fibre, diminuant les déchets. Les réacteurs à fission nucléaire constituent un des environnements les plus agressifs : la dose de rayonnement gamma est de l'ordre du GGy avec une forte fluence de neutrons et une température de fonctionnement supérieure à 300°C pour les réacteurs actuels, connus comme de génération III. Ce travail a été réalisé en collaboration avec la société AREVA, industriel français actif dans le domaine de l'énergie, dans le but de réaliser un capteur de température résistant à l'environnement d'un réacteur nucléaire de génération IV, réacteur à neutrons rapides refroidi au sodium liquide. La technologie actuellement utilisée, les thermocouples, présente une dérive de la mesure due au rayonnement et un temps de réponse d'une seconde. Afin de supprimer la dérive, de réduire le temps de réponse et d'augmenter la précision, un capteur de température à réseau de Bragg a été choisi. Pour comprendre le comportement d'un tel système dans un environnement difficile, nous avons utilisé une approche expérimentale basée sur des techniques complémentaires comme l'atténuation induite par le rayonnement, photoluminescence, résonance paramagnétique électronique et spectroscopie Raman / The nuclear industry shows an increasing interest in the fiber optic technology for both data communication and sensing applications in nuclear plants. The optical fibers offer several advantages and the sensors based on this technology do not need any electrical power at the sensing point, they have a quick response and they can be easily multiplexed: in the case of a temperature sensor, several thermocouples can be substituted by a single fiber, resulting in a decrease of the waste material. The fission reactors are a very harsh environment: it is characterized by the highest dose of gamma-rays, of the order of magnitude of GGy, besides a high flux of neutrons and high operating temperature (300°C for the current reactors, known as generation III). This work has been carried out in collaboration with AREVA, a French industrial conglomerate active in the energy domain, with the aim of realizing a temperature sensor resistant to the environment of nuclear reactor of generation IV, in particular a Sodium-cooled Fast Reactor. The currently used technology, the thermocouples, presents a drift of the measurement due to irradiation, that needs a calibration, and a long response time on the order of seconds. In order to remove the drift, to reduce the response time and to increase the precision, a Fiber Bragg Grating temperature sensor was chosen, in regard to all the advantages of the optical fibers. To understand the behavior of such system in a harsh environment, as the nuclear reactor core, we used an experimental approach based on complementary techniques such as radiation-induced attenuation, photoluminescence, electron paramagnetic resonance and Raman spectroscopies

Orientador : Carlos Kenichi Suzuki / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-04T01:44:29Z (GMT). No. of bitstreams: 1 Ono_Eduardo_M.pdf: 3494337 bytes, checksum: 6a111a737f2e9b27797fca1dc7c3fe90 (MD5) Previous issue date: 2004 / Resumo: Um novo processo VAD ("Vapor-phase Axial Deposition"), em desenvolvimento no Laboratório Ciclo Integrado do Quartzo - LIQC, FEM, UNICAMP, introduz uma série de inovações tecnológicas e maior viabilidade econômica sobre os atuais processos de fabricação de fibra óptica. Para a produção de uma fibra de alta qualidade, a uniformidade geométrica da preforma porosa, gerada na etapa de deposição do processo, possui grande relevância na uniformidade das características da fibra final, tais como a atenuação e a dispersão. Para o controle da geometria da preforma em deposição, desenvolveu-se um sistema em LabVIEW, para a plataforma PC, para atuar continuamente e em tempo real na etapa de deposição de modo a manter o diâmetro da preforma constante. Em sua essência, o sistema de controle realimentado, baseado no controlador PID, atua na velocidade do mecanismo de posicionamento da preforma em função do valor do diâmetro na região inferior da preforma. Esse diâmetro é obtido pelo processamento da imagem adquirida por uma câmera de vídeo CCD da região da preforma em deposição. Embora tenha sido desenvolvido para a escala laboratorial, o sistema mostrou bom desempenho e estabilidade, podendo ser empregado na produção industrial em grande escala de preformas para fibra óptica. Nesse sistema, variações dimensionais no diâmetro da preforma da ordem de 0,3 mm são corrigidos, obtendo-se uma precisão cinco vezes maior quando comparado a sistemas convencionais, favorecendo uma menor incidência de rejeitos de produção de preformas e, conseqüentemente, menor custo de produção / Abstract: An advanced V AD (Vapor-phase Axial Deposition) technique has been developed at Laboratory of Integrated Quartz Cycle - LIQC - FEM - UNICAMP. It introduces a series of technological innovations with a greater economical viability over actual optical fiber manufacturing processes. For a high quality optical fiber production, several steps and process parameters must be carefully set. The geometrical uniformity of the preform during the deposition stage is one of the most important parameter for the final uniformity, which determines the characteristics of the final fiber in terms of attenuation and dispersion. To control the preform geometry during the deposition, a computer system based on Lab VIEW platform was developed, to act continuously and in real time on the deposition stage, in order to maintain constant the preform diameter. In its essence, the feedback system, based on PID controller, acts on the speed of the preform positioning mechanism, according to the value of the diameter detected in. the deposition region. This diameter is obtained through the image processing grabbed from a CCD video camera. Although, it was developed in a laboratorial scale, the system showed a good performance and stability, which can be applied on an industrial mass production scale for fiber optics. In this system, dimensional variations in the order of 0.3 mm on the preform diameter can be corrected, that corresponds to a precision about 5 times better than that achieved by conventional industrial systems, with a benefit of a lower incidence of production rejects and, therefore, a lower production cost / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

[pt] A presente tese tem por objetivo estabelecer uma metodologia de caracterização metrológica de redes de Bragg do tipo I, tipo II e tipo regenerada estimando e validando estatisticamente o resultado de medição para medições de altas temperaturas voltadas para aplicações em sensoriamento. Além das telecomunicações, as fibras óticas estão sendo empregadas em aplicações de sensoriamento, visto que, a sílica que as compõem apresenta grande eficiência como meio de transmissão de dados. A crescente demanda por medição em alta temperatura nos processos industriais possibilitou o desenvolvimento de novas tecnologias de medição além das tecnologias tradicionais já utilizadas atualmente. Desta forma, criaram-se as condições necessárias para se introduzir uma nova tecnologia de medição de temperatura com redes de Bragg que apresenta algumas vantagens se comparadas com as tecnologias tradicionais de medição. Apesar de já existirem várias pesquisas a respeito de medição de temperatura com redes de Bragg, nenhuma delas aprofundou as questões metrológicas com as respectivas estimativas das incertezas de medição que envolve todo o processo de medição e caracterização de redes de Bragg em alta temperatura. A adaptação de um sistema tradicional de calibração de instrumentos de medição de temperatura foi projetado e desenvolvido, de tal forma que possibilitou a caracterização dos diferentes tipos de redes. Observou-se que os resultados de medição e as estimativas das incertezas de medição obtidos para todas as redes, se aproximaram satisfatoriamente dos modelos teóricos utilizados, confirmando a adequação dos sistemas de medição de temperatura e sensoriamento ótico. / [en] This thesis aims to establish a methodology for the metrological characterization of Bragg gratings type I, type II and type regenerated statistically thereby estimating and validating the measurement results for high temperature sensing applications. Beyond telecommunications applications, optical fibers are still used for optical sensing, since the silica fiber has great optical efficiency for data transmission. The growing demand for high-temperature measurements in industrial processes has enabled the development of new measurement technologies beyond the traditional technologies already in use today. Thus were created the conditions necessary to introduce a new technology of temperature measurement with Bragg gratings which presents some advantages compared with traditional technologies of measurement. Although there are several prior studies none of those examined the by others about temperature measurement with Bragg gratings, metrological issues, and is particular, the estimate of the measurement uncertainties surrounding the whole process of measurement and characterization of Bragg gratings at high temperature. The adaptation of a traditional system of calibration instruments for temperature measurement was developed and designed in such a way that allowed the characterization of different types of gratings. It was observed that the measurement results and the estimated uncertainties of the measurements obtained for all gratings, successfully approached the theoretical models used, confirming the adequacy of the measurement of temperature and optical sensing.

This master thesis deals with the possibility of separation of useful signal from noise using polarization of laser radiation. This thesis is structured into 5 thematic units. The first unit is focused on laser radiation and its properties. The second part contains a deeper focus on the polarization of radiation, its description and the possibilities of measuring the polarization states. The third part of the thesis is devoted to the design of the measuring chains and identification of used elements. Chapter four contains measurement of status of the polarization and its results. The last chapter analyzes particular measuring chains outputs according to their spectral characteristics.

Diploma thesis focuses on the theoretical analysis of precise time and stable frequency transfer. It describes what time and frequency is, their properites and options of their generation. Next part deals with different possibilities of time and frequency transfer especially using fiber optics. In the practical part equipment for analysing effects of temperature changes on precise time transfer is puted into operation. Arduino platform is used for monitoring temperature changes on fiber. For testing of frequency stability in variable temperature conditions of environmental chamber device is created using highly coherent laser.

Master thesis is focused on creating graphical user interface for the sensorical system based on Phase-OTDR. Theoretical part describes optical fibers, explains the principle of Bragg gratings, their production and their use in sensors. Methods of optical fiber attenuation and phase OTDR measurement are also described. Other part is focused on LabVIEW programming software and utilization of sensorical system and its components. Practical part deals with the user interface itself, which consists of two tabs. The first tab is designed for evaluation and display of measured data. The second tab is used to control and set up system components. Both of these tabs are further subdivided into other subtabs. Regarding the conclusion, further development of the program and options of hardware replacement for improving this sensorical system in the future will be discussed.

This thesis describes the problem of fiber gratings, focusing primarily on the use of Bragg's grids in the sensor. It describes the types of fiber mesh production, especially the method of writing with a phase mask. The next part deals with the possibilities of using apodization in fiber optic systems. It deals with the various functions that can be used to describe apodization. The following part describes the moire principle, especially the method of overlapping two phase masks with a different period.

This work deals with the transmission of optical radiation modulated by a radio frequency signal through an optical fiber. Furthermore, it describes the principles of communication and area coverage. It points out the practical use of components located in the communication chain of this system. Explains the functionality of the properties and the division of individual components. It introduces the benefits and limitations of this system. It further describes the creation of a topology suitable for laboratory measurement of RoF technology. Provides experimental measurement of C-band parameters. Indicates the possible use of RoF technology using a wireless optical link. A part of the work is also a sample laboratory protocol.