Les verres de chalcogénures combinent plusieurs propriétés : une transparence étendue dans l’infrarouge, un indice de réfraction élevé (n>2) et de fortes propriétés non-linéaires. La réalisation de fibres optiques microstructurées (FOMs) permet d’exacerber les effets non-linéaires et notamment en faisant varier les paramètres optogéométriques des fibres (d et Λ). Ainsi, des fibres à propagation monomode peuvent être obtenues ou encore des fibres dont les applications potentielles concernent l’optique active avec la génération d’effets non-linéaires. La réalisation de telles fibres passent par la synthèse de verres de chalcogénures de haute pureté. Par conséquent, les bandes d’absorption limitant la transparence des fibres doivent être identifiées et limitées au maximum. Pour cela, le suivi et la qualification des éléments utilisés lors de la synthèse des verres doivent être entrepris. Un protocole de synthèse et de purification par traitements thermiques a été mis en place en ce sens. La technique pour élaborer les FOMs en verres de chalcogénures est le moulage. Elle consiste à couler un verre dans un moule entièrement réalisé en silice. Ce dernier présente la géométrie inverse de la fibre désirée. Cette méthode permet d’obtenir des géométries variées et reproductibles en passant par des fibres monomodes et multimodes avec des diamètres de cœur allant de 2 μm jusqu’à plus de 20 μm. La réalisation de sources infrarouges a été développée dans le manuscrit. Cela a été rendu possible dans un premier temps par la génération d’un supercontinuum à l’aide d’une fibre à cœur suspendu puis par la réalisation d’un laser à cascade quantique (QCL) couplé à une fibre monomode. De plus, une fibre à maintien de la polarisation (FMP) dans le moyen infrarouge, présentant une biréfringence de groupe de l’ordre de 10-3 a été élaborée grâce à l’évolution du moule de silice. De plus, un coupleur tout-optique, une fibre toute-solide et un faisceau de fibres infrarouges complètent les réalisations obtenues au cours de cette thèse. / Chalcogenide glasses combine several properties : large transparency in the infrared range, a high refractive index (n>2) and strong non-linear properties. The realization of microstructured optical fibers (MOFs) exacerbates non-linear effects more particularly by varying the opto-geometrical parameters of the fibers (d and Λ). Thus, single-mode propagation can be obtained and also generation of non-linear effects. The realization of high purity chalcogenide glasses is needed. In fact, absorption bands limiting the transparency of the fibers must be identified and minimized. For this, monitoring and qualification of components used in the synthesis of glasses should be undertaken. A protocol of synthesis and purification by heat treatment was implemented in this direction. The technique to elaborate MOFs is the casting method. It consists of flowing a glass on a silica mold. The geometry is the negative shape of the desired fiber. This method allows the realization of multimode or single-mode fiber in the 1-10 μm window. The realization of infrared sources was developed in the manuscript. The generation of a supercontinuum with a suspended-core fiber has been presented and also by the realization of a quantum cascade laser (QCL) coupled into a singlemode fiber. In addition, a polarization-maintaining fiber (PMF) having a group birefringence of the order of 10-3 was developed through the evolution of the silica mold. In addition, an optical coupler, an all-solid fiber and an infrared bundle were achieved during this thesis.

In this study, we will discuss the fabrication detail about the capillary optical fiber and microstructured optical fiber (MOF) from the preform manufacture to the drawing process and apply our capillary optical fiber in a temperature sensor device. First, we discuss the influence of the drawing parameters contribution for the fiber, and we will introduce how to design a preform and discuss how to keep our fibre geometry in drawing process by controlling the drawing parameters. For better fiber products, we need to make some important improvements such as fixing the preform geometry and designing the preform pressure or vacuum input path before the fiber drawing process. In the fiber drawing we want to control the fiber inner diameter and make the interval between three capillary tube disappear. We will solve these problems by different preform making methods or drawing tower hardware design and drawing parameter control. Now we can successfully make single ring hole MOFs by the capillary tube sealed method. But the hole structure is not as good as expectation. We will try to design a pressure and vacuum input device to replace the capillary tube sealed method. And help us to make better and more different MOF structures. We also used our capillary optical fiber to be a temperature sensor. We will describe the principle and the sensing sensitivity of our sensing device in this study. Our temperature sensing device shows a linear relationship between the temperature and operation wavelength, and the sensing sensitivity is 0.038nm/¢XC

Este trabalho de doutoramento propôs investigar novas configurações geométricas para as fibras ópticas microestruturadas a base de sílica. Aproveitando-se da flexibilidade que sua geometria proporciona, diferentes das fibras ópticas convencionais, foram propostas fibras ópticas microestruturadas com perfil tipo D atuando, especificamente, em duas aplicações distintas: fibras compensadoras de dispersão ou fibras altamente birrefringentes. Para o estudo teórico das fibras ópticas microestruturadas foram utilizados dois métodos numéricos: o método da Sobre-Relaxação Sucessiva (SOR) e o método de Arnoldi Implicitamente Reiniciado (IRAM). Foi necessário implementar o método IRAM para determinar os modos de mais alta ordem presentes em guias de onda multimodos, uma vez que o método SOR fornece apenas a solução para o modo fundamental. Neste contexto, as fibras ópticas microestruturadas com perfil D, propostas e investigadas neste trabalho, demonstraram ser extremamente promissoras para atuar na compensação da dispersão cromática ou no aumento do efeito da birrefringência. Foram projetadas fibras capazes de compensar a dispersão em banda larga, cobrindo as bandas de telecomunicações S, C e L, ou, ainda, fibras com um alto coeficiente de dispersão negativo em torno do comprimento de onda de 1550nm. Adicionalmente, verificou-se também que com as novas configurações propostas foi possível projetar fibras com elevado grau de birrefringência, sendo atrativas no projeto de fibras mantedoras do estado de polarização. / This work proposed to investigate new geometric configurations for the silica microstructured optical fibers. Based on their design flexibility, not usually found in conventional silica fibers, D-shape microstructured optical fibers were designed, specifically, for two different applications: dispersion compensation or high birefringence. For the theoretical analysis two numerical methods were used: the finite difference Successive Over Relaxation (SOR) method, and the Implicitly Restarted Arnoldi Method (IRAM). It was necessary to develop the IRAM method to determine the higher order modes inside the multimodo optical waveguide, since the SOR method is able to yield only the fundamental mode. In this framework, the D-shape microstructured optical fibers, which have been proposed and investigated in this work, proved to be extremely efficient for chromatic dispersion compensation and increasing the birefringent effect. Fibers have been designed in order to compensate the wideband dispersion, covering three entire telecommunication bands, namely: S-, C- and L- bands, simultaneously. Additionally, with these new proposed configurations it is possible to design high birefringent fibers, which are very attractive in polarization maintaining applications.

Este trabalho de doutoramento propôs investigar novas configurações geométricas para as fibras ópticas microestruturadas a base de sílica. Aproveitando-se da flexibilidade que sua geometria proporciona, diferentes das fibras ópticas convencionais, foram propostas fibras ópticas microestruturadas com perfil tipo D atuando, especificamente, em duas aplicações distintas: fibras compensadoras de dispersão ou fibras altamente birrefringentes. Para o estudo teórico das fibras ópticas microestruturadas foram utilizados dois métodos numéricos: o método da Sobre-Relaxação Sucessiva (SOR) e o método de Arnoldi Implicitamente Reiniciado (IRAM). Foi necessário implementar o método IRAM para determinar os modos de mais alta ordem presentes em guias de onda multimodos, uma vez que o método SOR fornece apenas a solução para o modo fundamental. Neste contexto, as fibras ópticas microestruturadas com perfil D, propostas e investigadas neste trabalho, demonstraram ser extremamente promissoras para atuar na compensação da dispersão cromática ou no aumento do efeito da birrefringência. Foram projetadas fibras capazes de compensar a dispersão em banda larga, cobrindo as bandas de telecomunicações S, C e L, ou, ainda, fibras com um alto coeficiente de dispersão negativo em torno do comprimento de onda de 1550nm. Adicionalmente, verificou-se também que com as novas configurações propostas foi possível projetar fibras com elevado grau de birrefringência, sendo atrativas no projeto de fibras mantedoras do estado de polarização. / This work proposed to investigate new geometric configurations for the silica microstructured optical fibers. Based on their design flexibility, not usually found in conventional silica fibers, D-shape microstructured optical fibers were designed, specifically, for two different applications: dispersion compensation or high birefringence. For the theoretical analysis two numerical methods were used: the finite difference Successive Over Relaxation (SOR) method, and the Implicitly Restarted Arnoldi Method (IRAM). It was necessary to develop the IRAM method to determine the higher order modes inside the multimodo optical waveguide, since the SOR method is able to yield only the fundamental mode. In this framework, the D-shape microstructured optical fibers, which have been proposed and investigated in this work, proved to be extremely efficient for chromatic dispersion compensation and increasing the birefringent effect. Fibers have been designed in order to compensate the wideband dispersion, covering three entire telecommunication bands, namely: S-, C- and L- bands, simultaneously. Additionally, with these new proposed configurations it is possible to design high birefringent fibers, which are very attractive in polarization maintaining applications.

Ce manuscrit de thèse présente le développement et l’étude d’une source supercontinuum dans l’infrarouge moyen pour une application de détection de gaz par spectroscopie d’absorption. L’étude des sources supercontinuum est basée sur la propagation non-linéaire d’impulsions ultracourtes dans un verre de tellurite de composition 80TeO2-10ZnO-10Na2O (% molaire) et utilisé sous trois formes différentes, à savoir un échantillon massif sous la forme d’une pastille, puis une fibre microstructurée à cœur suspendu fabriquée à partir de ce même verre, et enfin cette dernière fibre ultérieurement effilée (aussi appelée « taper »). Ces trois options d’utilisation s’adaptent à différents types de sources lasers disponibles commercialement et permettent d’optimiser la génération d’une source de lumière recouvrant une gamme très large de fréquences. Chaque observation expérimentale est accompagnée de simulations numériques correspondantes qui mettent en évidence les différents mécanismes physiques et dynamiques de la génération de supercontinuum. La première étude reporte la mise en œuvre d’une source supercontinuum induite par filamentation dans l’échantillon massif, à l’aide d’un laser femtoseconde de forte énergie (plusieurs micro-Joules), et associée à une caractérisation spectro-angulaire complète. Puis, l’accent a été mis sur la génération de supercontinuum dans les fibres optiques microstructurées à cœur suspendu (avec ou sans taper) à l’aide de sources lasers femtosecondes nano-Joules. Une étude complète de fabrication et d’optimisation des propriétés de ces fibres avec ou sans taper a été menée, notamment pour améliorer les contributions linéaires et non-linéaires du guidage sur la propagation et les conversions de fréquences associées. Une source supercontinuum s’étalant de 0.6 à 3.3 µm (équivalent à 400 THz de largeur spectrale) est obtenue avec une fibre d’une longueur de 10 cm. Enfin, une source s’étalant de 0.9 à 2.6 µm, à l’aide d’un laser à fibre plus compact, a été développée grâce aux fibres microstructurées effilées pour une application de détection de gaz. Le principal objectif étant d’explorer les raies d’absorption au-delà de 2 µm, qui sont reconnues comme étant bien plus intenses et donc plus faciles à détecter. Un dispositif expérimental de spectroscopie d’absorption par source supercontinuum dans une cellule multi-passage compacte a été mis en place avec succès pour la détection de méthane. / This work focuses on the development of mid-infrared supercontinuum light sources and their application for gas detection through absorption spectroscopy. The study of supercontinuum sources is based on nonlinear ultrashort pulse propagation in tellurite glass (80TeO2-10ZnO-10Na2O) and used in three different forms, namely a thin bulk sample, a microstructured suspended-core fiber, and a tapered suspended-core fiber. These technical means adapt themselves to distinct laser sources commercially available, thus optimizing the implementation of ultrawide-band infrared light sources. Experimental observations are compared to corresponding numerical simulations, thus pointing out the different underlying physical mechanisms of supercontinuum generation. The first study reports the filamentation-induced supercontinuum source in the tellurite glass bulk sample by means of a high-energy femtosecond laser (several micro-Joules) and associated with a complete spectro-angular mapping of light distribution. Then, the main task is related to supercontinuum generation in microstructured suspended-core fibers (with or without tapering) using nano-Joule femtosecond laser sources. A complete analysis of the fiber design was performed, especially to enhance linear and nonlinear wave propagation for efficient frequency conversion processes. As a result, a supercontinuum source covering the 0.6-3.3 µm region (i.e., 400-THz spectral bandwidth) is obtained in a 10-cm tapered fiber segment. Finally, another supercontinuum source covering the 0.9-2.6 µm region, pumped by a very compact fiber laser, was developed, in particular for its application in a gas detector system. The main goal is to explore absorption lines beyond 2 µm, which are known to be more intense and then easier to detect. A complete experimental setup for supercontinuum absorption spectroscopy based on a compact multi-pass cell was successfully developed for methane detection.

Made available in DSpace on 2016-03-15T19:38:12Z (GMT). No. of bitstreams: 1 Igor da Silva Ramos.pdf: 1622777 bytes, checksum: 186a77eaabf846baf8466f41da580a23 (MD5) Previous issue date: 2009-02-03 / Fundo Mackenzie de Pesquisa / This work studies, through systemic modeling a microstructured optical fiber used in a module for dispersion compensation and Raman amplification for optical communication systems. The use of this device compensates the dispersion in a range of frequencies not covered by conventional dispersion compensating fibers and, simultaneously, amplifies the signal in order to reach longer transmission distances. In particular, dispersion compensation and amplification is demonstrated in the O Band (1260 nm up to 1360 nm) for systems operating at 10 and 40 Gbps. For this purpose, the parameters of a real microstructured optical fiber model are used in the VPI TransmissionMaker numerical simulation software through which is possible to evaluate the performance of the device. The performance evaluation is carried out through Bit Error Rate (BER) as a function of link distance and transmission channel wavelength. / Este trabalho estuda através de modelamento sistêmico, uma fibra óptica microestruturada utilizada em um módulo de compensação de dispersão e amplificação Raman de sistemas ópticos. O uso deste dispositivo compensa a dispersão em faixas de freqüência não cobertas por fibras de compensação de dispersão convencionais e simultaneamente amplifica o sinal a fim de permitir maiores distâncias de transmissão. Em particular, compensação de dispersão e amplificação são demonstradas na banda O (1260 nm a 1360 nm) para sistemas operando a taxas de 10 e 40 Gbps. Para isso, são utilizadas as características de um modelo de fibra microestruturada real no software de simulação numérica VPI TransmissionMaker por meio do qual é possível avaliar o desempenho deste dispositivo. A avaliação de desempenho é feita através de curvas de taxa de erro de bits (BER, do inglês Bit Error Rate) em função do comprimento do enlace e comprimento de onda do canal de transmissão.