Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Neste trabalho, alÃm dos capÃtulos que envolvem a teoria e definiÃÃes, foi basicamente divido em trÃs estudos: Primeiro (capÃtulo 4), apresentamos uma investigaÃÃo numÃrica do desempenho de um filtro passa-banda totalmente Ãptico composto por um acoplador direcional duplo seguido de duas grades de Bragg simetricamente iguais gravadas nos seus braÃos de saÃda. Esta configuraÃÃo caracteriza um InterferÃmetro de Michelson com caracterÃsticas de um filtro add/drop. As caracterÃsticas de transmissÃo (T), taxa de extinÃÃo (XR) e âcrosstalkâ (XT) foram estudadas a partir da aplicaÃÃo de um sinal CW (onda contÃnua) na entrada do dispositivo. A teoria de modos acoplados e o mÃtodo de Runge Kutta de 4a ordem foram aplicados, respectivamente para resolver as equaÃÃes diferenciais acopladas. Este à o primeiro estudo feito considerando a nÃo linearidade do acoplador e a linearidade das grades de Bragg. O dispositivo apresenta um comportamento altamente nÃo-linear em funÃÃo do defasamento entre as amplitudes dos feixes refletidos e em funÃÃo da potÃncia de entrada. Num segundo momento (capÃtulo 5) apresentamos a propagaÃÃo e chaveamento de pulsos ultracurto (~2ps) usando um interferÃmetro de Michelson de Fibras Ãpticas. Neste estudo o desempenho do interferÃmetro à estudado como uma funÃÃo das caracterÃsticas nÃo lineares do acoplador e das grades de Bragg. Os estudos numÃricos foram feitos a partir das equaÃÃes de modos acoplados resolvidas usando o mÃtodo de Runge-Kutta de 4 ordem. As caracterÃsticas de chaveamento do pulso foram analisadas em funÃÃo da potÃncia de entrada e do defasamento aplicado em uma das grades de Bragg. As caracterÃsticas de transmissÃo (T), coeficiente de ExtinÃÃo (XR), âcrosstalkâ (XT), fator de compressÃo (FC). Utilizamos trÃs valores de potÃncia de entrada: abaixo da potÃncia critica (P0=1W), igual a potÃncia crÃtica (P0=1,73W) e acima da potÃncia crÃtica (P0=1,95W). AtravÃs deste estudo, pode-se verificar que a transmissÃo, taxa de extinÃÃo, âcrosstalkâ e fator de compressÃo dependem da potÃncia da bombeio inserida no dispositivo e da defasagem aplicada. O interferÃmetro de Michelson em fibras implementa componente de grande importÃncia para aplicaÃÃes em redes Ãpticas, como os demultiplexadores add/drop. Este dispositivo tem atraÃdo bastante interesse no campo das telecomunicaÃÃes devido a sua alta capacidade de taxas de transmissÃo. Num terceiro momento foi apresentado um estudo de simulaÃÃo numÃrica do desempenho da codificaÃÃo e decodificaÃÃo de pulsos Ãpticos curtos (ps) em sistemas OCDMA (Optical Code Division Multiple Access â acesso VIII mÃltiplo por divisÃo de cÃdigo no domÃnio Ãptico) baseado em FBG (Fiber Bragg Grating â grade de Bragg em fibra Ãptica) onde os cÃdigos sÃo inseridos atravÃs de saltos discretos na fase Ãptica (Âπ). Para geraÃÃo de pulsos codificados foram utilizados cÃdigos de Gold obtidos analiticamente. Analisamos como a inserÃÃo de cÃdigos adicionais afetam a autocorrelaÃÃo e correlaÃÃo cruzada. O interferÃmetro de Michelson inicialmente estudado no capÃtulo 4 foi utilizado para propagaÃÃo e chaveamento de sinais codificados. Baseados nas caracterÃsticas de TransmissÃo (T) e Taxa de extinÃÃo (XR) fizemos um estudo do dispositivo como multiplexador /demultiplexador add/drop na recuperaÃÃo de pulsos codificados. / This work, in addition the chapters which involves both theory and definitions, was basically divided three studies: First (chapter 4),we present a numerical investigation of the performance of a bandpass filter composed of an all-optical directional coupler, followed by two double bars Bragg recorded symmetrically equal outputs in their arms. This configuration features a Michelson interferometer with characteristics of an add/ drop filter. The transmission characteristics (T), extinction rate (XR) and "crosstalk" (XT) were studied based on the application of a CW signal (continuous wave) into the device. Theory of coupled modes and the Runge Kutta fourth order were applied respectively to solve the coupled differential equations. This is the first study considering the nonlinearity of the coupler and the linearity of Bragg gratings. The device features a highly nonlinear behavior as a function of dephasing between the amplitudes of the reflected beams and depending on the input power. In a second step (section 5), the propagation and switching of ultrashort pulse (~ 2PS) Michelson interferometer using an optical fiber. In this study the performance of the interferometer is studied as a function of the nonlinear characteristics of the coupler and Bragg gratings. The numerical studies were made from the coupled mode equations solved using the Runge-Kutta 4th order. The pulse switching characteristics were analyzed as a function of input power and applied to one dephasing Bragg gratings. The transmission characteristics (T), extinction coefficient (XR), "crosstalk" (XT), the compression factor (CF)and shape of the pulses were analyzed for different values of phase and different input powers. We use three values of input power: below the critical power (1W = P0), equal to the critical power (P0 = 1.73W) and above the critical power (P0 = 1.95W). Through this study, it is found that the transmission rate of extinction, "crosstalk" and compression factor depends on the power of the pump device inserted into the gap and applied The Michelson interferometer fiber implement major component with applications in optical networks, such as demultiplexers add/drop. This device has attracted considerable interest in the field of telecommunications due to its ability of high transmission rates. In the third place was presented a numerical simulation study of the performance of encoding and decoding of short optical pulses (ps) systems OCDMA (Optical Code Division Multiple Access based on FBG (Fiber Bragg Grating ) where codes are inserted through discrete jumps in the optical phase ( π). For generation of coded pulses were used Gold codes obtained analytically. We look at how the inclusion of additional codes affect the autocorrelation and cross correlation.The Michelson interferometer initially studied Chapters 4 was used for propagation and switching of encrypted signals. Based on the characteristics of transmission (T) and extinction rate (XR) did a study of the device as multiplexer/demultiplexer add / drop in the recovery of coded pulses.

First two chapters of this paper deals with the division of optical fiber sensors, digital signal processing and includes price comparison of four experimental sensors. In chapter three analysis, description and evaluation of measurment has been demonstrated on Mach - Zehnder interferometer. Last chapter is about application for signal analysis from vibration sensors. Description contains snippets from source code and graphical user interface. This paper includes three fields - fiber optics, digital signal processing and creation of application - and thanks to them it provides solid basis for study of optic fiber sensors.

This diploma thesis deals with comparsion of 2x2 and 3x3 couplers. There is also description of issue of the Michelson interferometer and its use as a sensor. This sensor is very good at detecting vibrations. Part of the work is description of simulation of Michelson interferometer with 3x3 coupler as vibration sensor and localization of vibration on optical fiber by Michelson and Mach-Zehnder interferometer.

High Spectral Resolution Lidar (HSRL) is a backscatter lidar technique that employs an optical/spectral filter to distinguish between particulate (Mie) and molecular (Rayleigh) backscattered light. By separating the two types of returns, higher accuracy measurements are possible that will enable improved climate models, air quality measurements, and climate forecasting. A spaceborne HSRL instrument can provide great impact in these areas by enabling near-continuous measurements across the Earth, however the optical filter technology has typically been too complex for reliable long-duration space flight due to the need for complicated and costly electro-optic feedback loops, extra alignment detectors, and additional laser sources. Furthermore, these complexities limit the filter from use in other applications. In this research, a high-performance, ultra-narrowband interferometric optical filter with a specific thermo-optical behavior has been designed and built. The interferometer has been designed such that it can be reliably adjusted/tuned by simply monitoring and adjusting the temperature. The greatly reduced operational complexity was made possible through high-accuracy thermal characterization of the interferometer materials, combined with detailed Structural-Thermal-Optical-Performance (STOP) modeling to capture the complicated interactions between the materials. The overall design process, fabrication procedures, and characterization of the optical filter are presented. / Doctor of Philosophy / LiDAR (an acronym for Light Detection and Ranging) is a technology that can be used to measure properties of the atmosphere. It is similar to radar, but uses much smaller light waves rather than larger radio waves, enabling more detailed information to be obtained. High Spectral Resolution Lidar (HSRL) is a lidar technique that uses a high precision optical filter to distinguish between light that scatters from particulates (such as dust, smoke, or fog) and light that scatters from molecules (such as oxygen, nitrogen, or carbon dioxide) in the atmosphere. By separating the two types of backscattered light, higher accuracy measurements are possible that will enable improvements in climate models, air quality measurements, and climate forecasting. A spaceborne HSRL instrument can provide great impact in these areas by enabling near-continuous measurements across the Earth; however, the optical filter technology has typically been too complex for reliable long-duration spaceflight due to the need for complicated and expensive additional hardware. In this research, a high-performance HSRL optical filter that can be reliably operated by simply monitoring and adjusting the temperature has been designed, built, and tested. The greatly-reduced operational complexity has been made possible through a new process that enables more accurate prediction of the complicated interactions between the materials of the optical filter. This process is based on a combination of high-accuracy characterization of the materials and detailed structural-thermal-optical-performance (STOP) modeling. The overall design process, fabrication procedures, and characterization of the optical filter are presented.

Les modes de gestion et de représentation des territoires ancestraux autochtones sont encore aujourd’hui largement enclavés dans des structures rhétoriques colonialistes. Les notions de propriété privée et de frontière étatique, les mythes de la terra nullius et de la découverte, la dominance de l’écriture et la dévaluation de l’oralité, sont autant de préceptes sur lesquels s’appuient à ce jour les outils textuels législatifs et géopolitiques canadiens. Ainsi, les épistémologies autochtones se trouvent marginalisées et délégitimées au sein des lois, des cartes nationales et de certains traités, qui s’imposent comme des cadres naturalisés de création, de transmission et de négation des connaissances spatiales. Lors de processus de revendications territoriales, certains acteurs et actrices politiques se consacrent à une autochtonisation des vocabulaires et méthodologies discursives des arènes juridique et législative, parvenant à y tailler des espaces de résurgence pour les voix autochtones. Néanmoins, un tel exercice de traduction culturelle s’avère souvent hasardeux et unidirectionnel, pouvant mener à une instrumentalisation ou à une dénaturation des savoirs autochtones. Cette thèse porte sur les stratégies développées par des artistes et auteur.es autochtones qui démantèlent, autochtonisent et outrepassent les outils textuels étatiques. Elle vise à démontrer que leur articulation de récits intimes, intergénérationnels et mythologiques comme matrices théorisantes permet une réactivation des réseaux relationnels holistes qui se trouvent à la base même des lois, des pratiques de gestion territoriale et, ultimement, des modes de formation identitaire autochtones évacués des enceintes coloniales. Nous proposons ainsi que les notions de souveraineté territoriale, mémorielle et rhétorique y sont imbriquées dans une triangulation dynamique qui prend racine dans des réalités locales, tout en trouvant écho dans des réseaux transcommunautaires élargis. Dans les œuvres de Nadia Myre, Lawrence Paul Yuxweluptun et Alan Michelson, notamment, de même que dans les écrits théoriques ou fictionnels de Gerald Vizenor et Taiaiake Alfred, les textes coercitifs comme la Loi sur les Indiens sont soit démantelés par le biais de grammaires visuelles endogènes et de structures narratives ancestrales réactualisées, soit extraits de l’enceinte législative et projetés en des espaces de réflexions dialogiques, hétérogènes et non coloniaux. De plus, les artistes Sonny Assu, Olivia Whetung et Christi Belcourt, de même que les autrices Leanne Betasamosake Simpson et Mishuana Goeman, entre autres, initient selon nous, par leurs discours de respatialisation décoloniale, un changement paradigmatique plutôt qu’un simple renversement des relations d’autorité déséquilibrées établies et portées par les cartes nationales et cadastrales. Les récits en résurgence qui articulent leurs représentations contre-cartographiques sont récoltés et transmis par le biais de pratiques matérielles, performatives et affectives témoignant d’une survivance collective des épistémologies autochtones au sein de leurs espaces de formation identitaire, malgré les restructurations de ces territoires par des infrastructures et des discours cartographiques coloniaux. Nous souhaitons donc démontrer, par ce travail d’analyse intertextuelle, que les philosophies holistes, expérientielles et intergénérationnelles ancestrales, retravaillées au moyen des arts, des langues et des récits, fournissent des méthodologies d’effritement de vastes structures rhétoriques hégémoniques, de même que des modèles de création d’espaces transnationaux et décoloniaux d’où émergent de nouveaux possibles. / Territorial management policies and dominant ways of depicting Indigenous lands are still today extensively entrenched in colonial structures and ideologies. The concepts of private property and state borders, the doctrines of discovery and terra nullius, the devaluation of oral traditions and the domination of writing systems, are only but a few of the precepts that underpin contemporary legislative and geopolitical frameworks. Thus, Indigenous epistemologies are often marginalized and delegitimized within legislative texts, national cartography, and certain treaties, which act as all-encompassing frames of knowledge production, dissemination, and negation. During land claim negotiations, First Nations representatives devote themselves to indigenizing the vocabularies and methodologies that shape legal spheres, effectively carving out spaces of resurgence for Indigenous voices. However, such endeavors of cultural translation can prove hazardous and unidirectional, sometimes leading to Indigenous knowledges being manipulated or distorted. This thesis focuses on the strategies developed by Indigenous artists and writers who dismantle, indigenize, and bypass those state-sanctioned texts through their productions. We wish to demonstrate that these creators articulate personal, collective, and mythological stories as theoretical frameworks. In doing so, they reactivate the kinship networks that also shape ancestral laws, land management practices and modes of identity formation, which are often dismissed within colonial discourses. We argue that territorial, rhetorical, and memorial sovereignties are therefore entwined in a dynamic triangulation that simultaneously stems from a local context, and resonates on a transnational level. In Nadia Myre, Lawrence Paul Yuxweluptun, and Alan Michelson’s artworks, as well as in Gerald Vizenor and Taiaiake Alfred’s theoretical and fictional writings, coercive texts such as the Indian Act are either dismantled through the revitalization of endogenous visual grammars and ancestral narrative structures, or extracted from the legislative sphere and relocated in spaces of dialogical, heterogenous, and non colonial reflection. Moreover, we argue that artists such as Sonny Assu, Olivia Whetung, and Christi Belourt, as well as authors like Leanne Betasamosake Simpson and Mishuana Goeman, initiate a paradigmatic change rather than a simple reversal of the skewed authority dynamics conveyed by national cartography and cadastral maps. The stories they use to structure their counter-mapping discourses are harvested and transmitted through material, relational, and performance practices that attest to the survivance of Indigenous epistemologies, despite the restructuring of their traditional spaces of identity formation by colonial infrastructures and mapping tools. Throughout our inter-textual analyses, we wish to demonstrate that holistic, experiential, and ancestral philosophies, when revisited through artworks and stories, provide both decolonial methodologies that may erode hegemonic rhetorical structures, and tools to generate transnational spaces of resurgence.

This master’s thesis deals with the impact of atmospheric turbulence on phase changes of a free space optical signal. This problematic is investigated by the interferometric method. A part of the thesis is focused on the phenomenon of atmospheric turbulence. Then the physical effect of interference is discussed and optical interferometers are described. The experimental part of the thesis is focused on measurement of phase shift of optical signal by interferometric method. The result of the thesis is to determine how phase shift of an optical beam depends on the strength of turbulence.

In this work is describe anatomy and physiology of the cornea. The following are the primary non-inflamatory degeneration of the cornea. Then describe the physical principles diagnostic devices for cornea – keratometer, pachymeter, Michelson interferometr and optical coherence tomography (OCT). At the end of the theoretical introduction is describes the principle of laser correction surgery – LASIK. The practical part is divided into two main objectives. The first task is propose an algorithm for automatic detection of corneal surface and then calculation of corneal thickness and size of the chamber angle in Matlab. The aim of the second task is image flap analysis for boundary detection.