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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.
21

Circuito equivalente e extração dos parâmetros em função da corrente de amplificadores ópticos a semicondutor / Equivalente circuit and parameters extraction as function of the bias current of semiconductor optical amplifiers

Figueiredo, Rafael Carvalho, 1982- 16 August 2018 (has links)
Orientadores: Evandro Conforti, Napoleão dos Santos Ribeiro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-16T11:21:52Z (GMT). No. of bitstreams: 1 Figueiredo_RafaelCarvalho_M.pdf: 10424465 bytes, checksum: b93608291545cc7a53e52e2050a3dc39 (MD5) Previous issue date: 2010 / Resumo: Apresenta-se a modelagem de um circuito elétrico equivalente e a extração de parâmetros de amplificadores ópticos a semicondutor (SOA), a partir de um modelo para lasers semicondutores. Foi realizado um estudo do comportamento da impedância de um SOA em chip, sem encapsulamento, em função da corrente de polarização e em ampla faixa de frequência . de 300 kHz a 40 GHz. A modelagem do circuito equivalente da montagem, a qual é cascateada com os modelos da região ativa do SOA, é apresentada para correntes abaixo e acima da operação em transparência. A metodologia utilizada para a extração dos parâmetros dos elementos parasitas que compõe o circuito é descrita; resultados obtidos através de simulações em programa comercial (Agilent ADS) são comparados com medidas experimentais obtidas em mesa óptica. São apresentados ainda resultados teóricos da impedância do SOA quando desconsiderada a presença dos elementos parasitas da montagem. A modelagem e extração dos parâmetros realizada para o chip foi repetida para SOAs encapsulados, também apresentando boa concordância entre teoria e experimento, reforçando a viabilidade da abordagem utilizada / Abstract: The equivalent electric circuits and its parameters.extraction of semiconductor optical amplifiers (SOA) are attained based on a diode-laser model. Additionally, the impedance behavior of a SOA-chip (without package) was measured as function of the bias current in wide frequency range, from 300 kHz to 40 GHz. In these procedures, the microwave setup used for the SOA current injection was also characterized and its equivalent circuit obtained. Next, a theoretical analysis is developed for this setup for currents below and above the transparency condition. A methodology for the parameters extraction of parasitic elements is also described, as well as the results obtained through simulations using the Agilent ADS software, compared with the experimental data. The optical bench used in the experiments is also described, and theoretical results illustrates the SOA impedance without parasitic elements. The equivalent circuits with parameters.extraction were also obtained for packaged SOAs, with good agreement between theory and experiment, conforming the employed methodology / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica
22

Estudo de células de cristais líquidos termotrópicos calamíticos nemáticos e suas aplicações como sensores eletro-ópticos de tensões elétricas / not available

Marcos Rodrigues Costa 06 October 2000 (has links)
Esta pesquisa mostrou a viabilidade técnica da utilização de células de cristais líquidos nemáticos (CLNs) como elementos sensores eletro-ópticos de tensões elétricas eficazes (RMS). Duas foram as filosofias abordadas na concepção desses sensores: a modulação em amplitude da intensidade da luz polariza atuando em células transmissivas e a tensão de Freedericksz atuando em células reflexivas. Os sensores baseados na primeira filosofia foram denominados, nesta pesquisa, de sensores de escala de cinza (EC) e os segundos de sensores de gráfico de barras (GB). O sensor EC foi desenvolvido para aplicações em altas tensões. Este sensor é constituído por um divisor de tensão capacitivo, onde o braço de baixa tensão é composto por uma célula de cristal nemático torcida (CLNT). O sensor EC alia as vantagens dos tradicionais sistemas eletro-ópticos, tais como a imunidade às interferências eletromagnéticas (IEM); o alto isolamento elétrico proporcionado pela fibra óptica; com as vantagens de ser um sistema com um simples aparato óptico, então indutivo. O sensor GB mostrou-se mais versátil que o sensor EC. Neste sensor o braço de alta tensão do divisor de tensão capacitivo foi confeccionado na própria célula. Além disso, o sensor GB é menos sensível a influências térmicas, sendo neste caso mais indicado para aplicações de campo. Além das vantagens citadas acima, os sensores desenvolvidos apresentam as características de possuírem baixo custo, facilidade de instalação, versatilidade e empregarem tecnologia nacional. Também neste trabalho, foram estudados e determinados modelo físicos e elétricos que melhor representam o comportamento das células de CLNs. Os modelos físicos permitiram expandir o conhecimento sobre o comportamento de dispersão dielétrica presente nestes materiais devido ao movimento de impurezas iônicas; ao movimento molecular, e ao acúmulo de cargas espaciais nas interfaces entre as camadas de alinhamento e o cristal líquido, e também, auxiliaram na compreensão dos parâmetros físicos que influenciam no comportamento anisotrópico da permissividade dielétrica e da condutividade elétrica dos CLNs. Os modelos elétricos, além de auxiliarem na compreensão dos mecanismos físicos auxiliando com isso a proposição de modelos fenomenológicos, também mostraram-se uma poderosa ferramenta a ser aplicada na otimização de processos de fabricação e no desenvolvimento de dispositivos utilizados na confecção de mostradores de informação (LCDs). Estes modelos elétricos foram testados e utilizados em programas computacionais dedicados à simulação de circuitos elétricos, e puderam auxiliar sobremaneira no desenvolvimento do sensor GB. / In this research the technical viability of the usage of nematic liquid crystal (NLC) cells as sensor elements of effective electric voltage (RMS) is presented. Two approaches were adopted for the conception of these sensors: the modulation in width of the intensity of the polarized light acting in transmissive cells and the voltage of Freedericksz acting in reflexive cells. The sensors based on the first approach were termed grayscale sensors and the second were bargraph sensors. A grayscale sensor was developed for applications in high voltage. This sensor is constituted by a capacitor voltage divider, where the low voltage arm is composed of a cell of twisted nematic liquid crystal (TNLC). The grayscale sensor combines the advantages of traditional electro-optical systems, such as immunity to the electro-magnetic-interference (EMI) and the high electric insulation provided by the optical fiber; associated to characteristics of being a simple optical apparatus and a non-inductive system. The bargraph sensor has shown to be more versatile than the grayscale sensor. In this bargraph sensor the high voltage arm of the capacitor voltage divider was built in the CLNT cell itself, facilitating its use in both high and low voltages. Besides, the bargraph sensor is less sensitive to thermal influences, being in this case more suitable to field applications. In addition to the advantages mentioned above, both sensors developed showed characteristics of low cost, installation easiness, versatility and indigenous technology. Due to the need of establishing parameters for the development of the electric voltage sensor, also in this research, physical and electric models that best represent the behavior of NLC cells were obtained. The physical models allowed expanding the knowledge about the behavior of dielectric dispersion present in these materials due to the movement of ionic impurities, molecular movement, and the accumulation of space charge in the interfaces between the alignment layers and the liquid crystal. These models have also contributed to the understanding of the physical parameters that influence the anisotropic behavior of both dielectric permittivity and electric conductivity of NLCs. Besides, the electric models helped in the understanding of the physical mechanisms aiding in the proposition of phenomenological models. They have also proved to be a powerful tool to be applied in the optimization of production processes, as well as in the development of devices used in liquid crystal displays (LCDs). These electric models were tested and used in software for the simulation of electric circuits and could aid greatly in the development of bargraph sensors.
23

Development of new photonic devices based on barium titanate in silicon

Castera Molada, Pau 01 September 2017 (has links)
Integration of complex optical functionalities with high performance will lead to a huge development in the field of nanophotonics for a broad range of applications. Silicon photonics is currently the leading technology for the implementation of low-cost photonic integrated devices. The great potential of this technology relies on its compatibility with the mature silicon integrated circuits manufacturing based on complementary metal-oxide semiconductor (CMOS) processes widely used in microelectronic industry and the availability of high quality silicon-on-insulator wafers, an ideal platform for creating planar waveguide circuits that offers strong optical confinement due to the high index contrast between silicon (n=3.45) and silicon dioxide (n=1.45). In order to keep improving the performance of photonic devices on silicon, the integration of CMOS compatible materials with unique properties shows up as an excellent opportunity to overcome the current limitations in silicon while offering unprecedented and novel capabilities to the silicon platform. In this way, barium titantate (BaTiO3) stands out as one of the most disruptive candidates. The work developed in this thesis is essentially focused on the design, fabrication and characterization of an electro-optic modulator based on a hybrid BaTiO3 on silicon structure for the implementation of high performance electro-optic functionalities with beyond state-of-the art performance that currently cannot be afforded in silicon photonics technology. / La integración de funcionalidades ópticas con alto rendimiento llevará a un gran desarrollo en el campo de la nanofotónica para un amplio abanico de aplicaciones. Actualmente, la fotónica de silicio es la tecnología líder para la implementación de dispositivos fotónicos integrados a bajo coste. El gran potencial de esta tecnología reside en su compatibilidad con las maduras técnicas de fabricación de circuitos integrados de silicio basadas en los procesos "complementary metal-oxide semiconductor" (CMOS) ampliamente utilizados en la industria microelectrónica y la disponibilidad de disponer de obleas de silicio sobre aislante de alta calidad, una plataforma ideal para crear circuitos de guía de ondas planas que ofrecen un fuerte confinamiento óptico debido al alto contraste índices entre el silicio (n=3,45) y el dióxido de silicio (n=1,45). Para poder mejorar el rendimiento de dispositivos fotónicos en silicio, la integración de materiales con propiedades excepcionales y compatibles con los procesos de fabricación CMOS surge como una excelente oportunidad para superar las actuales limitaciones de la tecnología de silicio al mismo tiempo que ofrece oportunidades novedosas y sin precedentes en la plataforma de silicio. En este sentido, el material titanato de bario (BaTiO3) se postula como uno de los candidatos más prometedores. El trabajo desarrollado en esta tesis está esencialmente enfocado en el diseño, fabricación y caracterización de un modulador electro-óptico basado en una estructura híbrida de BaTiO3 en silicio para la implementación de funcionalidades electro-ópticas de alto rendimiento más allá del estado del arte de las que no se puede disponer actualmente en la tecnología de fotónica de silicio. / La integració de funcionalitats òptiques amb alt rendiment portarà a un gran desenvolupament en el camp de la nanofotònica per a un ampli ventall d'aplicacions. Actualment, la fotònica de silici és la tecnologia capdavantera per a la implementació de dispositius fotònics integrats a baix cost. El gran potencial d'aquesta tecnologia resideix en la seva compatibilitat amb les madures tècniques de fabricació de circuits integrats de silici basades en els processos "complementary metal-oxide semiconductor" (CMOS) amplament utilitzats en la indústria microelectrònica i la disponibilitat de disposar d'hòsties de silici sobre aïllant d'alta qualitat, una plataforma ideal per crear circuits de guia d'ones planes que ofereixen un fort confinament òptic a causa de l'alt contrast d'índexs entre el silici (n=3,45) i el diòxid de silici (n=1,45). Per poder millorar el rendiment de dispositius fotònics en silici, la integració de materials amb propietats excepcionals i compatibles amb els processos de fabricació CMOS sorgeix com una excel·lent oportunitat per superar les actuals limitacions de la tecnologia de silici al mateix temps que ofereix oportunitats noves i sense precedents en la plataforma de silici. En aquest sentit, el material titanat de bari (BaTiO3) es postula com un dels candidats més prometedors. El treball desenvolupat en aquesta tesi està essencialment enfocat en el disseny, fabricació i caracterització d'un modulador electro-òptic basat en una estructura híbrida de BaTiO3 en silici per a la implementació de funcionalitats electro-òptiques d'alt rendiment més enllà de l'estat de l'art de les quals no es pot disposar actualment a la tecnologia de fotònica de silici. / Castera Molada, P. (2017). Development of new photonic devices based on barium titanate in silicon [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86197 / TESIS
24

Piezoelectric transduction of Silicon Nitride photonic system

Hao Tian (12470151) 28 April 2022 (has links)
<p>  </p> <p>Integrated photonics has provided an elegant way to bring the table-top bulky optical systems from the research lab to our daily life, thanks to its compact size, robustness, and low power consumption. Over the past decade, Silicon Nitride (Si3N4) photonics has become a leading material platform, benefiting from its record-low loss, large Kerr nonlinearity, and compatibility with the foundry process. However, the lack of electro-optical effect makes it challenging to actively tune the Si3N4 photonic circuits for advanced applications, such as LiDAR, spectroscopy, and atomic clocks. During my PhD research, I have developed a new platform of piezoelectric control of Si3N4 photonics through stress-optical effect. By integrating an<br> Aluminum Nitride (AlN) piezoelectric actuator, I demonstrated the tuning of Si3N4 optical microring resonator at sub-microsecond speed with nano-Watt power consumption. Microwave frequency (GHz) acousto-optic modulation (AOM) is realized by exciting high-overtone bulk acoustic wave resonant modes (HBAR), which are tightly confined in an acoustic Fabry-Pérot cavity. Maximum of 9.2 GHz modulation is achieved which falls into the microwave X-band. </p> <p><br></p> <p>The applications of the Piezo-on-Photonic platform are extensively explored in the quasi-DC and high frequency regimes. By working as a stress-optical tuner at low frequency, it allows me to actively tune a Kerr frequency comb into different states, and stabilize it over several hours, which can serve as the light source for the next-generation chip-based LiDAR engine. On the other hand, the GHz frequency AOM has helped me demonstrate a magnetic-free integrated optical isolator, a device that transmits light in only one direction. Three AlN HBAR actuators are integrated closely on the same Si3N4 microring resonator, which generate an effective rotating acoustic wave and break the transmission reciprocity of the light. A maximum of 10 dB isolation is achieved under 300 mW total radiofrequency power, with minimum insertion loss of 0.1 dB. Finally, the application of the same technique in quantum microwave to optical converter is theoretically analyzed, showing potential for building future quantum networks. The initial experimental attempt and outlook for future improvements are investigated. </p> <p><br></p> <p>In conclusion, this thesis investigated a novel Piezo-on-Photonic platform for flexible and efficient control of the Si3N4 photonic system, and its applications in a wide variety of advanced devices are demonstrated, with the potential of being key building blocks for future optical systems on-chip.  </p>
25

Electro-optical And All-optical Switching In Multimode Interference Waveguides Incorporating Semiconductor Nanostructures

Bickel, Nathan 01 January 2010 (has links)
The application of epitaxially grown, III-V semiconductor-based nanostructures to the development of electro-optical and all-optical switches is investigated through the fabrication and testing of integrated photonic devices designed using multimode interference (MMI) waveguides. The properties and limitations of the materials are explored with respect to the operation of those devices through electrical carrier injection and optical pumping. MMI waveguide geometry was employed as it offered advantages such as a very compact device footprint, low polarization sensitivity, large bandwidth and relaxed fabrication tolerances when compared with conventional single-mode waveguide formats. The first portion of this dissertation focuses on the characterization of the materials and material processing techniques for the monolithic integration of In0.15Ga0.85As/GaAs self-assembled quantum dots (SAQD) and InGaAsP/InGaAsP multiple quantum wells (MQW). Supplemental methods for post-growth bandgap tuning and waveguide formation were developed, including a plasma treatment process which is demonstrated to reliably inhibit thermally induced interdiffusion of Ga and In atoms in In0.15Ga0.85As/GaAs quantum dots. The process is comparable to the existing approach of capping the SAQD wafer with TiO2, while being simpler to implement along-side companion techniques such as impurity free vacancy disordering. Study of plasma-surface interactions in both wafer structures suggests that the effect may be dependent on the composition of the contact layer. The second portion of this work deals with the design, fabrication, and the testing of MMI switches which are used to investigate the limits of electrical current control when employing SAQD as the active core material. A variable power splitter based on a 3-dB MMI coupler is used to analyze the effects of sub-microsecond electrical current pulses in relation to carrier and thermal nonlinearities. Electrical current controlled switching of the variable power splitter and a tunable 2 x 2 MMI coupler is also demonstrated. The third part of this dissertation explores the response of In0.15Ga0.85As/GaAs SAQD waveguide structures to photogenerated carriers. Also presented is a simple, but effective, design modification to the 2 x 2 MMI cross-coupler switch that allows control over the carrier distribution within the MMI waveguide. This technique is combined with selective-area bandgap tuning to demonstrate a compact, working, all-optical MMI based switch.
26

Active Silicon Photonic Devices Based on Degenerate Band Edge Resonances

Wood, Michael G. January 2016 (has links)
No description available.
27

Angle of Arrival Estimation Using Spectral Interferometry and a Photonic Link

Andrew J Putlock (18436287) 29 April 2024 (has links)
<p dir="ltr">Accurately locating a radio-frequency (RF) emitter is imperative in the defense sector, and passive direction finding systems are intriguing due to relatively low cost. This approach involves using the time difference between a signal’s impact at equispaced antennas to determine the location of the emitter, a particular challenge for wideband waveforms operating near the noise floor. Microwave photonic systems have been demonstrated for passive direction finding. These techniques possessed drawbacks, such as reliance on the incoming signal’s bandwidth, dependence on laser power, or the inability to recover an angle from wideband pulses. This thesis presents a novel approach to passive direction finding by translating the methods of spectral interferometry from the optical domain to RF. Spectral interferometry involves interfering a time-delayed reference pulse with a “signal” pulse that has passed through an unknown system. By removing the spectral phase of the reference pulse from the resulting interferogram, the spectral phase of the uncharacterized system is recovered. This enables direction-finding for many waveforms, including the wideband low peak power chirps frequently used in radar. Incorporating an analog optical delay line into both a hard-wired RF interferometer and a two-element antenna array demonstrated spectral interferometric processing of chirped signals with up to 1 GHz instantaneous bandwidth. The technique extracted accurate delays and angles to within 2$\degree$ throughout testing. This approach only requires the imposed delay be longer than the autocorrelation of the bandwidth limited pulses. With additional backend processing, this method could simultaneously determine the angle and classify the incoming signal.</p>
28

Análise óptica de sistemas eletro-ópticos por meio do cálculo da função de transferência de modulação / Optical analyze of electro-optical systems by modulation transfer function calculus

Barbarini, Elisa Signoreto 13 April 2012 (has links)
Um grande número de equipamentos utilizam sistemas ópticos ou eletro-ópticos em suas estruturas, dentre esses equipamentos tem-se os microscópios, telescópios, equipamentos médicos, câmeras de satélites, entre outros. Com isso a necessidade de métodos e ferramentas que auxiliem na determinação do desempenho e da qualidade dos sistemas ópticos é crescente. Um dos métodos mais utilizados para realizar a análise de sistemas ópticos é a determinação da Função de Transferência de Modulação (Modulation Transfer Function - MTF). A MTF representa uma verificação quantitativa e direta da qualidade da imagem, e, além disso, é um teste objetivo que pode ser utilizado em sistemas ópticos concatenados. Esse trabalho apresenta a implementação de um software, denominado de SMTF (Software Modulation Transfer Function), para cálculo da MTF de equipamentos eletro-ópticos. O software foi utilizado para realizar o cálculo da MTF do Retinógrafo Digital, Imageador Termal e Microscópio Cirúrgico Oftalmológico. A informação da MTF auxilia na análise do alinhamento e medição da qualidade óptica, e também define o limite de resolução dos sistemas ópticos, por meio do gráfico da MTF. Os resultados obtidos, com o Retinógrafo e o Imageador Termal, foram comparados com os valores teóricos adquiridos pelo Zemax, que é um software utilizado para desenvolvimento e análise de lentes ou conjuntos ópticos. Já para o Microscópio os resultados obtidos da MTF foram comparados com os resultados obtidos pela MTF medida do Microscópio marca Zeiss, considerado como padrão de qualidade de Microscópios Oftalmológicos. Os resultados obtidos demonstram que o software apresentou ótimo desempenho permitindo uma análise direta e objetiva do comportamento de sistemas ópticos. Com auxílio do software foi feito o alinhamento do Retinógrafo Digital e do Imageador Termal e foi verificada a qualidade da imagem do Microscópio Cirúrgico Oftalmológico. / A number of devices use optics or electro-optics in their structures, such as microscopes, telescopes, medical equipments, satellites cameras, among others. The need for methods and tools that assist in determining the performance and quality of optical systems is increasing. One of the methods most used to perform analysis of optical systems is to measure the Modulation Transfer Function (MTF). The MTF represents a direct and quantitative verification of the image quality, and moreover, it is an objective test that can be used in concatenated optical systems. This paper presents the implementation of software, called SMTF (Software Modulation Transfer Function), in order to calculate the MTF of electro-optical systems. The software was used for calculating the MTF of Digital Fundus Camera, Thermal Imager and Ophthalmologic Surgery Microscope. The information MTF aids the analysis of alignment and measurement of optical quality, and also defines the limit resolution of optical systems, from the graph of MTF. The results obtained with the Fundus Camera and de Thermal Imager were compared with the theorical values acquired by the Zemax, wich is a software used for analysis and development of optical assemblies or lenses. For the Microscope, the results were compared with MTF measured of Microscope Zeiss model, which is the quality standard of ophthalmological microscope. The results show that the software has a good performance by allowing a straightforward analysis of the behavior of optical systems. With the aid of the software was made to align the Fundus Camera and the Thermal Imager and the image quality of Surgical Microscope Ophthalmology was verified.
29

Pré-processamento digital de imagens obtidas na faixa espectral do infravermelho distante / Digital image processing in the longwave infrared spectral range

Bittencourt, Thiago de Morais Gonçalves 14 September 2012 (has links)
Este trabalho apresenta a pesquisa e desenvolvimento de algoritmos de pré-processamento digital de imagens para câmeras térmicas não refrigeradas na faixa espectral do infravermelho distante. O estudo de câmeras infravermelhas é uma questão estratégica, uma vez que tem aplicações militares, civis e científicas. Este trabalho define a concepção e implementação de algoritmos de pré-processamento de imagem necessários para obter imagens com baixo ruído e alto contraste, tais como: correção de não-uniformidade, substituição de pixels defeituosos, geração de histograma, aumento de contraste e processamento de saída do pixel, com taxa de 30 quadros por segundo, utilizando detector não-resfriado com matriz de plano focal de 320 x 240 pixels. Neste trabalho todos os algoritmos foram implementados em software para se obter resultados rapidamente e, assim, facilitar a validação dos códigos. Foram gerados resultados de caracterização eletro-óptica do sistema montado com indicação das principais figuras de mérito que norteiam o estudo desta tecnologia, tais como: componentes de ruído tridimensionais, potência equivalente de ruído, responsividade e relação sinal-ruído. Os resultados indicam que os algoritmos de pré-processamento de imagem propostos aumentam a qualidade da imagem a ser exibida, e os resultados das figuras de mérito calculadas sobre o vídeo digital mostram que todas as métricas apresentaram resultados satisfatórios. / This work aims to present the research and development of digital image processing algorithms for uncooled LWIR thermal camera in Brazil. The study of an infrared thermal camera is a strategic issue since that has more and more applications in military, judicature, rescue, industry, hospital and science areas. This work describes the design and implementation of all image-processing algorithms required to obtain high-performance images with low noise and high contrast, such as: functions for non-uniformity correction of sensor deficiencies, dead-pixel replacement algorithms, histogram generation, contrast enhancement methods and output pixel processing with frame rate of 30 frames per second based on 320 x 240 Uncooled Focal Plane Array (UFPA). In this work all algorithms was implemented in software to get results quickly and to facilitate the validation of computer codes. There are some results of electro-optical characterization on the assembled system, indicating the main figures of merit that guide the study of this technology, such as: 3D noise components, noise equivalent power (NEP), signal transfer function (SiTF) and noise equivalent temperature difference (NETD). The results indicate that the proposed imageprocessing algorithms increase the quality of the corrected image, and the test results through the digital video of the infrared camera show that all metrics are in accordance with its nominal value.
30

Micro modulateur spatial de lumière transmissif pour modulation de phase et d’amplitude / Transmissive micro spatial light modulator for phase and amplitude modulation

Abelard, Clément 20 November 2018 (has links)
Le LETI possède un savoir-faire permettant de réaliser des micro modulateurs spatiaux de lumière (Spatial Light Modulators, SLMs) réalisés en technologie microélectronique sur silicium, ayant des très grandes résolutions et de très petits pas de pixels. Le LETI souhaite utiliser une technologie LCD particulière (la technologie IPS) dont d’une part les performances électro-optiques dans le domaine des micro-écrans ne sont pas connues mais d’autre part permet de garder des coûts réduits et de réduire le nombre d’étapes de fabrication. L’objectif de cette thèse est d’évaluer sur la base de simulations puis de réalisations techniques, les performances d’un micro-SLM IPS utilisé en modulation de phase et d’amplitude.Les recherches effectuées au cours de cette thèse portent sur 4 axes d’études. Le premier axe consiste à la recherche et à l’essai d’un logiciel spécifique (LCDMaster) permettant de simuler des cellules à cristaux liquides ainsi que des électrodes flottantes. Le second axe consiste à étudier en fonction du design du pixel et des différents modes d’alignements des cristaux liquides (Homogène, vertical et twisté) avec un pilotage de type IPS, les performances en modulation de phase. Les meilleurs résultats sont obtenus pour un alignement vertical fournissant un déphasage de 2 Pi. De plus, les performances d’un dispositif d’optique adaptative intégrant le SLM étudié ont été investiguées. Le troisième axe d’étude, consiste avec le même logiciel à investiguer sur les performances d’un SLM à cristaux liquide avec un pilotage de type IPS utilisant un alignement homogène en modulation d’amplitude (étude statique et dynamique). Cette étude permet également d’étudier les possibilités de diminution du temps de réponse de la cellule. Cette étude a aboutie à deux designs de SLM. Le premier design avec deux niveaux d’électrodes séparés par un isolant permettant de reproduire un effet type « cage de faraday ». La seconde a permis de diminuer de manière drastique le temps de réponse. Le quatrième axe de recherche consiste à tester des prototypes basés sur ces deux designs pour vérifier les performances obtenues en simulation grâce à un banc de caractérisation électro-optique. Des résultats concordants ont étés obtenus et de nouveaux types de SLM à pilotage IPS proposant un temps de rafraichissement rapides se rapprochant de l’état de l’art ont donc pu être désignés et caractérisés. / LETI possesses an expertise allowing to realize Spatial Light Modulators (SLMs) made in microelectronic technology on silicon, having very high resolutions and very small pixel steps. LETI wishes to use a specific LCD technology (IPS technology), on the one hand the electro-optical performances in the field of micro-display had to be investigated but on the other hand allows to keep costs down and reduce the number of manufacturing steps. The objective of this thesis is to evaluate on the basis of simulations and technical achievements, the performance of a micro-SLM IPS used in phase modulation and amplitude.Our investigations have been carried out on four major areas of study. The first axis is the search and testing of a specific software (LCDMaster) to simulate liquid crystal cells and floating electrodes. The second axis according to different designs of pixel and the different liquid crystal alignment modes (Homogeneous, vertical and twisted) with an IPS type control, to investigate the performances in modulation phase. The best results were obtained for a vertical alignment providing a phase shift of 2π. In addition, the performance of an adaptive optics device integrating the studied SLM has been investigated. The third axis of study focused on the performance investigation of a liquid crystal SLM with an IPS-type control using a homogeneous alignment in amplitude modulation (static and dynamic study). This study also makes it possible to study the possibilities of reducing the response time of the cell. It resulted in two SLM designs. The first design with two levels of electrodes separated by an insulator to reproduce a Faraday type effect. The second has drastically reduced the response time. The fourth area of research consists in testing prototypes based on these two designs to validate the performances obtained in simulation. Concordant results have been obtained and new types of IPS-controlled SLMs with state-of-the-art refreshing times have thus been designated and characterized.

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