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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Estudo do desempenho do Multiplexador/Demultiplexador add/dropbaseado na configuraÃÃo do InterferÃmetro de Michelson de fibras Ãpticas para aplicaÃÃes em sistemas OTDMA e OCDMA / Study the performance of the multiplexer/demultiplexer add/drop based on the Michelson interferometer configuration for fiber for applications in optical systems OTDMA and OCDMA

Antonio Francisco Gomes Furtado Filho 02 March 2012 (has links)
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.
262

Técnicas de pós-processamento em fibras de cristal fotônico

Gerosa, Rodrigo Mendes 27 January 2011 (has links)
Made available in DSpace on 2016-03-15T19:37:37Z (GMT). No. of bitstreams: 1 Rodrigo Mendes Gerosa.pdf: 5257410 bytes, checksum: d0ee4897567ff7f2299a46312ebcc2f1 (MD5) Previous issue date: 2011-01-27 / Fundo Mackenzie de Pesquisa / In this work two techniques are described for post-processing photonic crystal fibers (PCFs), which were developed to change their guidance properties. The first technique consists of selectively closing holes of the PCF microstructure, thus allowing, among other things, to fill in some holes with materials such as liquids, polymers and nanoparticles. The other technique consists of selectively collapsing holes in the PCF cross-section using differential pressure and an optical fiber fusion splicer, and is based on techniques previously demonstrated for PCF tapering. With the first technique a simple and effective way of sealing liquid core fibers is demonstrated, which avoids evaporation. The study of PCFs with complex cores formed by the original core of a solid-core fiber and an oil-filled hole adjacent to the core was also undertaken with this technique and provided a strong interaction between light and the filled channel, as well as a high sensitivity to temperature (displacement of 5.35 nm/°C in the observed spectral structures). With the use of the second technique, the collapse of a hole adjacent to the solid core of a PCF allowed the development of a modal Mach-Zehnder allfiber interferometer, with a spectral modulation depth of 9.5 dB, which is similar to that of other PCF modal interferometers reported in the literature, and a sensitivity to temperature of -54 pm/°C, which is about 4 times higher than that of Bragg gratings in conventional optical fibers. The same technique was used to obtain optical coupling between two cores of a photonic crystal fiber with 3 initially uncoupled cores. / Nesse trabalho são descritas duas técnicas de pós-processamento em fibras de cristal fotônico (PCFs, do inglês Photonic Crystal Fibers) desenvolvidas para alterar suas propriedades de guiamento. A primeira consiste em fechar seletivamente buracos da microestrutura das PCF possibilitando assim, entre outras coisas, o preenchimento de alguns buracos com materiais como líquidos, polímeros e nanopartículas. A outra técnica consiste em se colapsar seletivamente buracos da seção transversal da microestrutura de uma PCF utilizando pressão diferencial e uma máquina de emendas para fibras ópticas, sendo baseada em técnicas previamente demonstradas para o afilamento (tapering) de PCFs. Com a utilização da primeira dessas técnicas é apresentada uma maneira simples e eficiente de se vedar fibras com núcleo líquido, evitando-se assim a evaporação. O estudo de PCFs com núcleos complexos, formados pelo núcleo original de uma fibra de núcleo sólido e um buraco adjacente ao núcleo preenchido por óleo foi também realizado com essa técnica, proporcionando uma grande interação da luz com o canal preenchido e uma alta sensibilidade a temperatura (deslocamento de 5,35 nm/°C nas estruturas espectrais observadas). Utilizado-se a segunda técnica, o colapso de um buraco adjacente ao núcleo sólido de uma PCF permitiu o desenvolvimento de um interferômetro modal de Mach-Zehnder totalmente a fibra, apresentando uma profundidade de modulação espectral de 9,5 dB, semelhante à de outros interferômetros modais em PCFs reportados na literatura, e uma sensibilidade a temperatura de -54 pm/°C, cerca de 4 vezes maior do que a de redes de Bragg em fibras ópticas convencionais. A mesma técnica foi utilizada para se obter o acoplamento óptico entre 2 núcleos de uma fibra de cristal fotônico com 3 núcleos inicialmente desacoplados.
263

Étude, développement et caractérisation des miroirs des interféromètres laser de 2ème génération dédiés à la détection des ondes gravitationnelles / Design, development and characterization of mirrors of the 2nd generation laser interferometers devoted to gravitational waves detection

Straniero, Nicolas 11 December 2015 (has links)
En cette fin d'année 2015, la construction de la 2e génération de détecteurs d'ondes gravitationnelles s'achève. Il s'agit des grands interféromètres de Michelson, dont les bras mesurent 3 km de long (Advanced Virgo) et 4 km de long (Advanced LIGO). Les ondes gravitationnelles, prédites par Einstein en 1916 dans sa théorie de la Relativité Générale n'ont pas été détectées de façon directe par la 1ère génération d'interféromètres. Mais aujourd'hui, la sensibilité a été augmentée d'un ordre de grandeur et le 100ème anniversaire de la théorie d'Einstein pourrait bien ouvrir officiellement l'ère de l'astronomie gravitationnelle. Si la sensibilité des nouveaux interféromètres est désormais exceptionnelle, c'est grâce aux avancées techniques et technologiques, et notamment grâce aux nouveaux miroirs des cavités Fabry-Pérot installés dans les bras de l'interféromètre. Cette thèse présente la conception, le développement et la caractérisation de ses miroirs aux qualités exceptionnelles. Elle s'intéresse aux pertes de lumière diffusée dans les cavités, pertes de diffusion générées par l'état de surface des miroirs et par les défauts d'uniformité des dépôts des couches minces à haute réflectivité. En étudiant la planéité des surfaces, nous verrons comment les modifications techniques du procédé de dépôt IBS ont permis d'améliorer la courbure et la planéité des surfaces. Nous verrons comment nous avons caractérisé ces surfaces avec l'interféromètre de Fizeau à décalage de longueur d'ondes. Nous montrerons enfin comment nous avons atteint les spécifications prévues lors de la conception des miroirs, diminuant les pertes de lumière diffusée dans les cavités Fabry-Pérot à un niveau encore inégalé de seulement quelques dizaines de ppm / In the year of 2015 the construction of the 2nd generation of detectors devoted to gravitational waves is going to be completed. These are large laser Michelson interferometers with arm respectively 3 km (Advanced Virgo) and 4 km (Advanced LIGO) in length. The gravitational waves, predicted by Einstein in 1916 within his theory of general relativity, have not been observed by the first generation of detectors. However, interferometers are now on the way of being ten times more sensitive than before, and so, on the 100th anniversary of the establishment of general relativity, the era of gravitational wave astronomy can start. If laser interferometer will be able to reach unprecedented sensitivity, it is thanks to new technological developments. In particular the new state of the art mirrors installed in the interferometer arms have exceptional performances. This thesis details the design, the development and the characterization of these remarkable large mirrors. My work will deal with the cavity optical loss due to the diffused light itself linked to the mirrors surface quality and to the high reflectivity coating uniformity. By studying the surface flatness, we will understand how it could be influenced by the deposition technique implemented in the coating machine. We will see also how to measure the mirror surfaces by wavelength shifting Fizeau interferometer. Finally, we will detail how we proceeded in order to reach the tight specifications for the mirrors, with in the end only tens of ppm for the cavity round trip losses
264

Polymer integrated Young interferometers for label-free biosensing applications

Wang, M. (Meng) 13 November 2012 (has links)
Abstract Integrated optical (IO) sensor allowing sensitive, label-free, real-time and multi-parameter monitoring of bio-molecular interactions are conventionally fabricated with inorganic dielectrics inherited from CMOS manufacturing technology. Polymers as complement materials to inorganic dielectrics are becoming to have an increasing market share for IO circuits in optical communications networks owing to its good optical properties, versatile processibility and low cost. This work aims at developing disposable low-cost biosensors based mainly on polymeric materials, with a performance comparable to inorganic-dielectric based IO biosensors. This thesis describes the development of polymer IO biosensors based on the Young interferometer (YI) transducer platform for ambient noise compensation and a complete periodic intensity fringe pattern. Three different waveguide configurations were utilized, taking into consideration operational simplicity, fabrication simplicity and enhanced sensitivity. Among the developed polymer biosensors, an unconventional interferometer structure: a vertically placed dual-slab waveguide interferometer and an inverted rib waveguide configuration were employed. To enhance the sensitivity of the waveguides, deposition of Ta2O5 high index coating was performed on the rib waveguide configuration. Along with the development of polymer biosensors based on the inverted-rib waveguide configuration, a fabrication process was also developed featuring UV-imprinting and spin coating. The simple two-step fabrication process demonstrated using a polymer mold is potentially transferable to the roll-to-roll manufacture process. Calibration of the developed sensors was performed by homogeneous refractive index (RI) sensing with glucose de-ionized water solutions. By investigating an antibody – antigen binding interaction involving C-reactive protein and its conjugates, this thesis confirmed the applicability of the developed sensors to specific molecule detection. Moreover, to establish the influence of water molecular absorption on measurement stability, an evaluation was carried out on the polymeric waveguide. Finally, the thesis presented a comparison between the developed sensors, exploring their sensitivities, stabilities, limits of detection (LODs) and other aspects related to operation and fabrication. The results indicated that the Ta2O5-coated polymer waveguide sensor had a high sensing capability. In homogeneous RI sensing, the achieved detection limits were 9×10-7 RIU (refractive index unit), i.e., three times the noise level, and 270 fg/mm2 for surface mass density. / Tiivistelmä Integroidulla optiikalla toteutetut anturit mahdollistavat biomolekulaarisen vuorovaikutuksen tutkimisen käyttäen herkkiä moniparametrisia ja merkkiaineettomia menetelmiä. Näiden bioantureiden valmistukseen käytetään tavallisesti CMOS-teknologian piiristä tuttuja epäorgaanisia puolijohteita ja eristemateriaaleja. Viime aikoina on kuitenkin polymeeristen materiaalien käyttöä integroidussa optiikassa tutkittu merkittävästi johtuen polymeerien hyvistä optisista ominaisuuksista, monipuolisesta työstettävyydestä ja edullisista kustannuksista. Tämän työn tarkoituksena on kehittää edullisia, kertakäyttöisiä, pääasiallisesti polymeerisistä materiaaleista valmistettuja bioantureita, jotka vastaavat suorituskyvyltään epäorgaanisista materiaaleista valmistettuja integroidun optiikan antureita. Tässä työssä kehitetyt polymeeriset integroidun optiikan bioanturit perustuvat Youngin interferometriin mahdollistaen ympäristökohinan kompensoinnin ja ne tuottavat pintavuorovaikutusten tutkimiseen jaksoittaisen interferenssikuvion. Työssä hyödynnettiin kolmea erilaista valokanavarakennetta huomioiden niiden käytön helppous, valmistuksen yksinkertaisuus ja mittausherkkyys. Yksi kehitetyistä polymeerisistä bioantureista koostui päällekkäisistä kerrostetuista polymeerikerroksista. Toisen tutkitun rakenteen toiminta puolestaan perustui käänteiseen harjannevalokanavaan. Mittausherkkyyttä parannettiin pinnoittamalla polymeerirakenne Ta2O5-pinnoitteella. Näin muodostui kerrostettu komposiittivalokanava, joka oli tässä työssä tutkittu kolmas sensorirakenne. Itse bioanturien lisäksi kehitettiin myös valmistusprosessi, jossa hyödynnettiin UV-painatusta ja nestefaasipinnoitusta. Tässä työssä havaittiin lisäksi, että kehitetty yksinkertainen valmistusmenetelmä on paitsi toimiva, myös mahdollisesti siirrettävissä rullalta rullalle valmistus- ja tuotantoteknologiaan. Kehitettyjen anturien kalibrointi suoritettiin homogeenisella taitekerroinmittauksella käyttäen liuoksia, jotka valmistettiin glukoosista ja deionisoidusta vedestä. Kehitettyjen anturien soveltuvuus spesifien molekyylien tunnistamista varten todennettiin tutkimalla vasta-aineiden ja antigeenien sitoutumisreaktioita ja vuorovaikutusta C-reaktiivisella proteiinilla ja sen konjugaateilla. Lisäksi työssä tutkittiin veden absorption vaikutusta mittauksen stabiilisuuteen. Tutkimuksessa suoritettiin vertailu kehitettyjen anturien ja niiden ominaisuuksien välillä kiinnittäen huomiota mittausherkkyyteen, stabiilisuuteen, määritys- ja toteamisrajoihin ja muihin anturien valmistukseen sekä käyttöön liittyviin keskeisiin piirteisiin. Tulokset osoittavat, että Ta2O5-pinnoitetun polymeerivalokanavan mittausherkkyys oli suurin vertailluista rakenteista. Homogeenisessä taitekerroinmittauksessa saavutettu määritys- ja toteamisraja oli 9×10-7 taitekerroinyksikköä (RIU). Pintamassatiheysmittauksessa saavuttu tulos oli 270 fg/mm2.
265

A polarization sensitive interferometer for Faraday rotation detection

LaForge, Joshua Michael 23 July 2007 (has links)
Time-resolved Faraday rotation (TRFR) is a pulsed laser pump/probe optical measurement used to characterize electron spin dynamics in semiconductor materials. A Mach-Zehnder type interferometer with orthogonally polarized arms is presented as a device for TRFR measurement that is superior to optical bridge detection, the traditional measuring technique, since Faraday rotation can be passively optically amplified via interference. Operation of the interferometer is analyzed under ideal conditions. Corrections to the ideal case stemming from imperfectly aligned optics, finite polarization extinction ratios, and an imperfect recombination optic are analyzed using a matrix transformation approach. The design of the interferometer is presented and chronicled. A description of the single-beam active control system utilized to stabilize the interferometer by continuous corrections to the optical path length of one arm with a piezoelectric actuator is given. Optical amplification by increasing the power in either arm of the interferometer is demonstrated and TRFR measurements taken with the interferometer at ambient temperatures are compared with measurements taken with the optical bridge. We find the interferometer to offer a detection limit on the order of 50 mrad at room temperature, which is five times more sensitive than the optical bridge. Isolation and stabilization of the interferometer were also successful in reducing signal noise to a level comparable with the optical bridge. Our results demonstrate that the interferometer is a better detection device for Faraday rotation under ambient conditions. In the immediate future, improvements to the control system should be made and experiments should be performed with high-quality samples at cryogenic temperatures to confirm that the interferometer performs as favorably under those conditions.
266

Recherche, développement et réalisation d'un contrôleur de Fabry-Perot de nouvelle génération / Research, development and realization of a new generation Fabry-Perot controller

Ouattara, Issa 25 June 2015 (has links)
L’équipe Physique des Galaxies du Laboratoire d’Astrophysique de Marseille a développé un nouveau type d'interféromètre de Fabry-Perot, équipé de trois actionneurs piézoélectriques amplifiés et de trois capteurs capacitifs permettant le contrôle de l'espacement et du parallélisme des lames de verres de l'ordre de 200 µm avec une précision de positionnement du nm.L'objectif visé de ce manuscrit, composé de 3 parties, est le pilotage de cet interféromètre. La première partie, composée des chapitres 1 et 2, présente les généralités sur l'interférométrie de Fabry-Perot puis décrit les instruments 3DNTT et BTFI où seront installés l'interféromètre de nouvelle génération et son contrôleur associé. La conception et la réalisation d'un amplificateur hybride en vue de la réduction des non-linéarités des actionneurs piézoélectriques mettent fin à cette partie.La deuxième partie, chapitres 3 et 4, décrit le développement et la réalisation du contrôleur. Pour cela, une démarche basée sur le concept du Co-design a été adoptée.Le contrôleur ainsi réalisé est composé d'une carte de développement Microzed dont le cœur est un système sur puce de la série Zynq 7000 EPP et d'une carte d'interfaçage comportant des convertisseurs 3 ADC et 3 DAC et des circuits d'alimentation. La troisième et dernière partie, chapitres 5 et 6, traite de la modélisation d'état de l’interféromètre de Fabry-Perot et de son contrôle : un contrôle classique basé sur la régulation PID et un contrôle robuste et optimal basé sur le filtrage de KALMAN. Cette dernière partie conclut sur les perspectives pouvant découler des contributions de ce travail sur le contrôle et la commande Fabry-Perot. / The Physics of Galaxies Team of Laboratoire d'Astrophysique de Marseille (LAM) has developed a new type of Fabry-Perot, with three amplified piezoelectric actuators and three capacitive sensors to control the spacing and parallelism of mirror plates of approximately 200 µm with a positioning accuracy of 3 nm.The purpose of this manuscript, consisting of 3 parts is the control of this interferometer.The first part, consisting of Chapters 1 and 2 presents the general interferometry Fabry-Perot and then describes 3DNTT and BTFI instruments which will be installed the next generation interferometer and its associated controller. The design and implementation of a hybrid amplifier to reduce non-linearities of the piezoelectric actuators (hysteresis and creep) end this first part.The second part, Chapters 3 and 4, describes the development and implementation of the controller.For this, an approach based on codesign concept was adopted. The thus achieved controller consists of a Microzed development board whose heart is a system on chip of the 7000 series Zynq EPP (FPGA + Dual-Core ARM Cortex A9) and an interface card with converters (3 ADC and 3 DAC) and power supply circuits.For the finalization of the controller, two steps are necessary: hardware design in Xilinx Vivado and software design in Xilinx SDK.The third and final section, chapters 5 and 6 deals with the Fabry-Perot space-state modeling and its control: a classic control based on PID control and a robust and optimal control based on KALMAN filtering. This last part concludes the outlook may result from contributions of this work on the monitoring and control of the Fabry-Perot.
267

Accéléromètre atomique double espèce 87Rb/39K aéroporté pour un test du principe d’équivalence / An airborne, dual species atom interferometer 87Rb/39K for an Equivalence Principle test

Gominet, Pierre alain 26 January 2015 (has links)
Lors de ces vingt dernières années, de nouvelles techniques de refroidissement et de manipulation des atomes ont permis le développement de senseurs inertiels basés sur l’interférométrie atomique. Le projet ICE est un interféromètre atomique double espèce qui a pour objectif de tester le principe d’équivalence faible. Afin d’augmenter la sensibilité de l’instrument, l’expérience est réalisée en micro-gravité lors de vols paraboliques à borde l’Airbus A300 zero-g de Novespace. L’interféromètre est composé de deux espèces atomiques (87Rb et 39K) ayant des transitions atomiques très proches (780 et 767nm). Ces longueurs d’ondes sont générées par une source laser bi-fréquence ultra-stable. Issue des technologies telecom et ensuite doublées en fréquence, elle est capable de résister aux contraintes des vols paraboliques. Précédemment, des mesures d’accélérations furent réalisées par un interféromètre Rubidiumen 1g et 0g en vol. Récemment, à l’aide d’un nouveau dispositif expérimental reposant sur une nouvelle enceinte à vide en titane, nous avons réalisé un des premiers accéléromètres Potassium. Cet atome présente en effet certaines difficultés à refroidir et à manipuler et demande un excellent contrôle des différents paramètres expérimentaux.Je présente ainsi dans ce manuscrit, les résultats obtenus avec le Rubidium et le Potassium sur le nouveau dispositif expérimental, et les récents progrès réalisés en vue d’un accéléromètre double espèce Rb/K. / During the last two decades, new techniques to cool and manipulate atoms has enabled the development of inertial sensors based on atom interferometry. The ICE project aims to verify the weak equivalence principle (WEP) using a compact and transportable dual-species atom interferometer. To make precise tests of the WEP, this experiment is performed in a micro-gravity environment during parabolic flights onboard the Novespace zero-g aircraft. The interferometer is composed of two atomic species (87Rb et 39K) with similar transition wavelengths (780 nm and 767 nm), which are derived from frequency-doubled telecom lasers. This ultra-stable laser source is able to withst and the parabolic flight and their rough conditions.In previous work, we have demonstrated measurements from a cold rubidium interferometer during the 1g and 0g phases during flights. Recently, we manage to carry out one of the first gravimeter with 39K in a new titanium vacuum system. This is a huge achievement because this atom is hard to cool down and to manipulate. I will present in this thesis, the results with Rubidium and Potassium on the newset-up, I we will report on recent progress toward a double species 87Rb/39K interferometer.
268

Senzor na bázi optovláknového interferometru / Sensor based on a fiber optic interferometer

Rozsypal, Filip January 2019 (has links)
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.
269

Využití a potlačování dvojlomných jevů v optovláknových senzorických aplikacích / Utilization and Suppression of Birefringence Phenomena in Optical Fiber Sensory Applications

Motúz, Rastislav January 2019 (has links)
The thesis deals with integral and distributed optical fiber sensors of electric current. In the area of integral sensors the analysis is performed by Jones matrix calculus and the simultaneous influence of induced circular and undesired linear birefringence using an ortho-conjugation retroreflector. Furthermore, the proposed conjugation loop variant using half-wave phase retarders is analyzed. The theoretical conclusions are confirmed by simulation and experimental measurement. In the field of distributed fiber optic sensors, analysis and simulation for the detection of plasma currents in thermonuclear fusion reactors, based on the POTDR technique, is performed. An improvement procedure is proposed for circular-shaped vacuum vessel reactors. Plasma current detection procedure in divertor-type reactors have been newly designed and simulated to investigate the effect of the OTDR detector noise on plasma current detection accuracy.
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Návrh automatického cyklu pro posuzování způsobilosti měření obrobkovou sondou na obráběcím centru / Design of an automatic cycle for assessing the measurement capability of a workpiece probe on a machining center

Mišún, Filip January 2021 (has links)
This diploma thesis describes the procedures of individual electronic compensations for CNC machines used to increase the accuracy of machines. This part is followed by the determining tolerance of the measuring and the influence of individual electronic compensations based on measured data using touch probe and calibrated standards according to VDA 5 norm.

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