L’objectif de ces travaux de thèse est de faire la preuve de concept, la validation expérimentale et la réalisation de système de mesure de champ électrique pour la caractérisation de câbles monoconducteur, multiconducteurs ou d’équipements de tension basse fréquence en environnement industriel. Ces travaux répondent à des problématiques de diagnostic énergétique ou de caractérisation d'appareillage haute tension. Le système permet une mesure vectorielle, sans contact des champs rayonnés par les conducteurs afin de s’affranchir de la nécessité d’habilitation électrique (aucune ouverture d’armoire électrique) et surtout sans nécessiter l’interruption de la chaîne de production. Les mesures sont faites en temps réel et permettent d’obtenir des informations sur les tensions, les phases ou encore les positions des conducteurs au sein d’un câble. Deux technologiques différentes sont proposées afin de répondre à cette problématique. La première technologie développée est basée sur l’effet Pockels et amène à la réalisation de sonde électro-optique totalement diélectrique donc non invasive pour la mesure. Cette sonde électro-optique permet, selon la configuration, la mesure des trois composantes du champ électrique. Cette première technologique est utilisée pour les systèmes haute tension. Une deuxième technologie, électrique, permet de répondre aux attentes des industriels en termes de coût et est utilisée pour des applications basse tension, comme le diagnostic électrique des câbles de tension. Un autre aspect a été développé dans le cadre des travaux de thèse afin de proposer une mesure puissancemétrique. Une technologique qui permet la mesure de champs magnétiques pour compléter les informations relatives aux câbles ou équipements industriels a été développé. Cette mesure se fait également sans contact et permet d’obtenir des informations sur le courant et ainsi déduire des informations sur la puissance. Le système électro-optique a permis de caractériser des systèmes haute tension tels que des câbles, des isolateurs ou encore des appareillages de commutation à isolation gazeuse (GIS). Le système électrique (pince puissancemétrique) a permis la caractérisation complète de câble d'énergie: position des conducteurs, tension des conducteurs, courant, phase, détection d'harmoniques ou mesure de décharges partielles. / The aim of this work is to propose the proof of concept, the experimental validation and the realization of electric field measurement system for the characterization of cables (single or multicore) or low frequency voltage equipment in industrial environment. The problematic are the energy diagnostics and high voltage device characterization. The developed system allows a conctact-less vector measurement of the fields radiated by drivers without requiring the interruption of the production chain. The measurements are made in real time and allow to obtain information about the voltage, the phase or the positions of the conductors in a cable. Two different technologies are proposed to address this problem. The first developed technology is based on the Pockels effect and leads to the realization of an electro optic probe totally dielectric and non invasive for the measurement. This electro optic probe allows, depending on the configuration, to measure the three components of the electric field. This technology is used, mainly, for high voltage applications. A second technology, based on electric sensors, is suitable for the industrial's expectations in terms of cost. It is used for low voltage applications such as electric diagnostics voltage cables. A complementary study has been developed to propose a wattmeter clamp. Thus, a technology allowing to measure the magnetic field has been implemented. This development is also contactless and provides information on the current in order deduce information on power. The electro-optical system has allowed characterization of high-voltage systems such as cables, insulators or switchgear gas-insulated (GIS). The electrical system (wattmeter clamp) offers a complete characterization of power cable: position of drivers, voltage drivers, current, phase, harmonic detection or measurement of partial discharge.

A montagem de um sistema que permite a detecção de modulação no coeficiente de absorção ótica, devido ao campo elétrico aplicado, foi concluída. A máxima sensibilidade atingida foi de &#916 K / K = 1,5 x 10-6 com resolução em comprimento de onda de 3 nm. O efeito Stark de 2&#170 ordem, na freqüência dupla da do campo elétrico aplicado foi medido para o centro F em KCl e KBr e comparado com provisões teóricas. Os valores obtidos para o KCl coincidem com os de Chiarotti, o que confirma o bom funcionamento do sistema, e diferem dos valores calculados teoricamente. Essa diferença é atribuída à correção do campo local. Os valores obtidos experimentalmente para a variação relativa do coeficiente de absorção foram: para KCl: &#916K / K = 2,93 x 10-5 (78&#176 K) para KBr: &#916K / K = 2,85 x 10-5 (78&#176 K) / The assembly of a system which allows the detection of modulation in the coefficient of optical absorption, due to the applied electrical field, was completed. The maximum sensitivity achieve was &#916 K / K = 1,5 x 10-6, in wave length, of 3 nm. The Stark effect of second order, in the frequency twice as that of the applied electrical field was measured for the center F in KCl and KBr and compared with theoretical previsions. The values obtained for KCl coincide with those of Chiarotti\'s, which confirms the good functioning of the system, and differ from the values calculated theoretically. This difference in ascribed to the correction of the local field. for KCl: &#916K / K = 2,93 x 10-5 (78&#176 K) for KBr: &#916K / K = 2,85 x 10-5 (78&#176 K).

La thèse montre des solutions pour la réalisation de circuits photoniques intégrés utilisant le caractère volumétrique et les très faibles pertes en propagation des solitons spatiaux. On s'intéresse aux éléments de base : interconnexions, sources et router optique (comme dispositif d'élaboration). Interconnexions et sources sont réalisé dans le niobate de lithium (LN) qui fournis des structures avec une très longue durée temporelle. Le fonctionnement d'un router optique est démontré dans le semiconducteur photo-réactif (PR) InP:Fe en raison de sa sensitivité aux longueurs d'onde infrarouges (IR) et à son temps de réponse rapide. On montre que les pertes en propagation dans les interconnexions solitoniques peuvent être réduites à nouveau en utilisant un faisceau en polarisation ordinaire qui augmente la variation d'indice de réfraction induite. La réalisation de sources intégrées solitoniques est étudié pour avoir émission en bleu à 400nm et en IR à 1530nm. Celles en bleu sont obtenues par génération de deuxième harmonique ; le rôle du bleu pour la formation des solitons est montré et ses propriétés physiques étudiées. Celles en IR sont obtenues en dopant le LN avec des ions (actifs) d'erbium. Leurs effets sur les paramètres PR sont présentés et les solitons spatiaux sont obtenus en excitant l'absorption soit du LN soit de l'erbium. L'amplification de la luminescence est étudié numériquement. Le routage optique dans le InP:Fe est obtenu en faisant interagir deux solitons cohérents et en changeant leur phase relative. L'augmentation de la séparation ou leur fusion est analysé en fonction de la distance entre eux, température et intensité de la lumière / Solutions for the realization of integrated photonic circuits with the advantages that spatial solitons offer, like their volumetric nature and the very low propagation losses are shown. Interconnections, sources and optical router (as signal elaboration device) are investigated. Interconnections and sources are experimentally demonstrated in lithium niobate (LN) that provides long-lasting structures thanks to its very long dielectric relaxation time. The optical router working principle is realized in the photorefractive semiconductor InP:Fe because of its sensitivity in infrared radiation and its fast response time. To improve solitonic interconnections, an analysis based on propagation losses in function of light polarization and LN anisotropy is done. The key role played by an ordinary polarized beam on the induced refractive index variation is exploited. Integrated sources in solitonic waveguides for the emission of blue at 400nm and of an infrared beam at 1530nm are investigated. Sources emitting in blue are obtained via a second harmonic generation process ; blue seed role in spatial soliton formation is demonstrated and its physical properties are investigated as well. The infrared one is achieved by doping LN with (active) erbium ions. Their effects on the photorefractive parameters are exploited and spatial solitons realized both pumping direcly erbium absorption lines and the LN ones. Luminescence amplification is studied numerically. Optical routing in InP:Fe is achieved by making two coherent solitons interact by changing their relative phase. Separation increasing or fusion is analyzed in function of mutual distance, temperature and light intensity

The infrared portion of the electro-magnetic spectrum is a challenging region in which to perform optical techniques, limited by both device efficiency and availability. In this dissertation, a new optical technique is introduced to facilitate polarization state measurement across the mid-IR. In addition, cadmium zinc telluride (CZT) is investigated as a potential new material suitable for electro-optic devices which function in the mid-IR, while also being characterized by other optical analysis methods. Thin film interference is discussed as it relates to optical techniques and electronic devices. A Stokes polarimeter is used to study the oxide development on the surface of CZT electronic devices, and the effect of natural thin films on substrates used in optical techniques is discussed. In particular, the impact of thin film interference on sum-frequency generation spectroscopy measurements of methyl group orientation are assessed. An FTIR source operated in step-scan mode is used to create a broadband, IR Stokes polarimeter which measures the polarization state of light from 2.5-11 μm simultaneously. Its design, involving two photo-elastic modulators and an analyzer, and theory are described in detail. This instrument is demonstrated by measuring linearly polarized light, and is applied to the measurement of the refractive index dispersion of quartz from 2.5-4 μm, which goes beyond the limits of literature values. Electro-optic crystals of CZT with electrodes of gold and indium are characterized at each wavelength in the mid-IR in terms of their electro-optic effects and apparent depolarization using the Stokes polarimeter. The material displays high-resistivity, allowing it to be operated with up to 5 kV applied DC voltage. The linear electro-optic effect is observed, but overall properties of the samples are found to be heavily dependent on the choice of metal for the electrodes. With a high-work function electrode material in gold, a large depletion region is created when high voltage is applied, which leads to a gradient in electric field throughout the material. This causes a beam of light transmitted through it to experience a distribution of electro-optic behaviours, which leads to overall depolarization of the light. Indium’s work function is lower than gold’s, and is closer to that of CZT. With indium electrodes, the electric field is found to be more consistent, and behaviour is much closer to ideal. The electro-optic effect of CZT is also characterized with AC applied voltage in order to assess its suitability to AC applied voltage applications. The power supply used for this was limited to 60 Hz, which precludes a complete characterization in this regard, but unexpected behaviour was seen. A methodology utilizing an oscilloscope and FTIR was developed in order to more completely understand the material response, and divergent behaviour with positive and negative voltage was found. / Graduate / 2018-12-18

Neste trabalho foi investigado o processo de relaxação em copolímeros metacrilicos funcionalizados com o grupo cromóforo 4-[N-etil-N-(2-hidroxietil)]amino-2\'-cloro-4\'nitro-azobenzeno (MMADRI3). Os copolímeros sintetizados foram caracterizados por espectrofotometria de visível e infravermelho, calorimetria diferencial de varredura, análise termogravimétrica e elipsometria. O triodo de corona foi utilizado para induzir a orientação dos cromóforos dipolares a temperaturas próximas da transição vítrea. Os valores do coeficiente eletroóptico linear r13 de filmes obtidos por derramento de solução podem alcançar 14 pm/V em amostras funcionalizadas com 43%de cromóforo.O efeito piezoelétricoé significativo para amostras contendo 4% de cromóforo sendo a sua origem atribuída à carga espacial. A relaxação orientacional dos cromóforos foi estudada medindo-se o decaimento do coeficiente eletroóptico e a relaxação dielétrica a diferentes temperaturas. O processo de relaxação foi interpretado utilizando a equação de Kohlraush-Williams-Watts (KWW) aplicada aos domínios do tempo e da freqüência. O tempo de relaxação característico &#964 e o parâmetro b da equação de KWW foram obtidos como função da temperatura desde a temperatura ambiente até acima da temperatura de transição vítrea. O parâmetro b à temperatura de transição vítrea aproxima-se de 0,6 valor que é atribuído a forças de curto alcance. As medidas dielétricas revelaram duas bandas de relaxação &#946 e &#945 respectivamente a baixas e a altas temperaturas. A relaxação a está relacionada com a transição vítrea e à desorientação dos cromóforos. A dependência de &#964 foi fundamentada nas equações de Arrhenius e de Vogel-Fulcher-Tarmnann-Hesse (VFTH), respectivamente a baixas e a altas temperaturas. Os parâmetros de VFTH encontram-se próximos dos considerados universais. O comportamento de &#964 em toda a gama de temperaturas, foi explicado pela equação de Adam-Gibbs, usando-se os parâmetros de VFTH. O resfriamento a taxas lentas após o processo de polarização aumenta substancialmente o tempo de relaxação e a sua energia de ativação. Os expoentes m e n do modelo de Dissado-Hill baseado na interação de multicorpos foram obtidos em função da temperatura. Os valores do parâmetro n ficam dentro do esperado pela teoria / The relaxation process of side-chain methacrylate copolymers functionalized with the nonlinear optical azo chromophore 4-[Nethyl-N-(2-hydroxyethyl)]-amino-2\'-chloro-4-nitroazobenzene (MMADR13) was investigated. The copolymers synthesized were characterized by visible and infrared spectrophotometry, differential scanning calorimetry, thermogravimetric analysis and ellipsometry. The corona triode was employed to induce the orientation of the dipolar chromophore at a temperature near the glass transition. The linear eletrooptic coefficient r13 of cast fllms can reach values as high as 14 pm/V in samples with 43% of chromophore contento The piezoeletric effect attributed to space charge was only significant in the lowest chromophore content samples (4%). Electrostriction was shown to affect to some extent the quadratic electrooptic measurements. The chromophore relaxation at different temperatures was investigated by both electrooptic decay and dielectric measurements. The relaxation process was interpreted using the Kohlraush-Williams-Watts (KWW) equation both in the time and frequency domains. From the KWW equation the characteristic relaxation time &#964 and the stretching parameter b were obtained from room temperature to temperatures above the glass transition. Near the glass transition b is ca 0.6 which is characteristic of short range interactions. Dielectric measurements revealed two relaxation bands, &#946 and &#945, at low and high temperatures, respectively. The &#945 relaxation was attributed to the glass transition and to the 10ss of chromophore orientational order. The temperature behavior of &#964 was interpreted by the Arrhenius and Vogel-Fulcher-Tammann-Hesse (VFTH) equations. at low and high temperatures. respectivelly. The VFTH parameters lie close to the so-called universal values. In addition the overall temperature dependence was explained by the Adam-Gibbs equation using the VFTH parameters. Using a small cooling rate after corona poling increases substantially the relaxation time and the activation energy .The power law exponents m and n. from Dissado-Hill manybody interactions model were obtained as a function of temperature. The n values are in the range of expected values for the many-body interactions model

This thesis presents the fabrication of a low loss hybrid waveguide electric field(E-field) sensor based on optical D-fiber. This novel E-field sensor is formed as part of a contiguous fiber resulting in a flexible and small cross-section device that can be embedded into electronic circuitry. The in-fiber nature of this sensor also eliminates the need for alignment and packaging that conventional sensors need. An optical fiber can detect electric fields when the core of the fiber is partially removed and replaced with an electro-optic polymer. This polymer causes a change in the index of refraction in the waveguide of the device when in the presence of an electric field. The change in the effective index of refraction changes the speed of the light in the vertical axis relative to the light in the horizontal axis creating a phase change between the two axes. This phase change can be detected as a change in the polarity of the light coming out of the fiber. The sensor is formed by partially etching out the core of a D-shaped optical fiber and depositing a polymer to form a hybrid waveguide. The polymer becomes sensitive to electric fields through corona poling. The typical corona poling process is not amenable to poling a polymer located in the fiber core. A method of poling conducive to an in-fiber device was developed and demonstrated. Using PMMA and DR1 for proof of concept, the operation of the first in-fiber hybrid waveguide electric field sensor is demonstrated. Etch depth, polymer composition, and polymer spin rate are optimized to provide strong interaction between the light and the sensing portion of the hybrid waveguide while maintaining low optical loss. High frequency testing was demonstrated to show that the effect is electro-optic. AC testing also allows the Epi of the sensors to be determined at lower electric fields than are required for DC testing, eliminating charge build up and electric field break down issues.

This dissertation explores techniques for improving slab-coupled optical fiber sensor (SCOS) technology for use in specific applications and sensing configurations. SCOS are advantageous for their small size and all-dielectric composition which permit non-intrusive measurement of electric fields within compact environments; however, their small size also limits their sensitivity. This work performs a thorough analysis of the factors contributing to the performance of SCOS and demonstrates methods which improve SCOS, while maintaining its small dimensions and high level of directional sensitivity. These improvements include increasing the sensitivity by 9x, improving the frequency response to include sub 300 kHz frequencies, and developing a method to tune the resonances. The analysis shows that the best material for the slab waveguide is an electro-optic polymer because of its low RF permittivity combined with high electro-optic coefficient. Additional improvements are based on changing the crystal orientation to a transverse configuration, which enhances the sensitivity due to a combined increase in the effective electro-optic coefficient and electric field penetration into the slab. The transverse SCOS configuration not only improves the overall sensitivity but increases the directional sensitivity of the SCOS. Lithium niobate and electro-optic polymer are both experimentally shown to exhibit minimal frequency dependent sensitivity making them suitable for broad frequency applications. Simultaneous interrogation of multiple SCOS with a single tunable laser is achieved by tuning the resonant wavelengths of KTP SCOS so their resonances overlap.

No description available.

<p> Lithium niobate has interesting characteristics such as the electro-optic effect, the acousto-optic effect, piezoelectricity and large nonlinear optical coefficients. Potential applications in MEMS field could be explored if microstructures are fabricated in lithium niobate substrates,. This thesis presents the fabrication and characterization of a lithium niobate MEMS device. As lithium niobate crystal is difficult to process using standard semiconductor techniques including both wet etching and dry etching, new methods are required to process lithium niobate. In our project, picosecond laser pulses were chosen to produce bridges on lithium niobate. Fabrication of grooves with high aspect ratio were attempted and grooves with clean morphology were obtained when laser pulses with low cutting speed, medium pulse energy, and large number of passes were employed. This shows picosecond laser machining is a viable method to process lithium niobate.</p> <p> Waveguides in Z cut lithium niobate crystal were fabricated using Ti-indiffusion techniques. After the fabrication of waveguides in lithium niobate, a SiO2 film with a thickness of 0.3μm was deposited as a buffer layer. Ti-Pt-Au electrodes for actuation function were then deposited through lift-off technique. Finally a bridge structure (80um in width and 600um in length) with a waveguide embedded in it was fabricated with picosecond laser. The insertion loss before and after laser machining was 6.99dB and 5.01dB respectively.</p> <p> Optical and electrical tests were performed in an effort to determine the resonance frequency of bridge. In the optical test, many bulk piezoelectric resonance peaks were presented in the frequency spectrum. After damping the vibration of substrate, these spikes disappeared and only a background noise with small spikes were obtained. As those small spikes are not reproducible, the optical test is not a viable method to determine resonance frequency of the bridge structure in our device. The electrical test was then carried out in a vacuum environment in order to find the resonance frequency. The spectrum presents a spike with large amplitude. However, the phase and amplitude of the spike remained the same when the vacuum condition was removed, which indicates the spike is not related to the resonance of the bridge. In summary, the resonance frequency of bridge structure could not be determined by these two approaches.</p> <p> Future work could involve directly investigating the material properties surrounding the machining region to see whether the piezoelectricity of the material has been damaged from laser ablation process. New laser machining process of lithium niobate may also need to be studied to avoid this damage to the substrate structure. Even though our device could not be driven to vibrate at its resonance frequency, it is worth making microstructures in lithium niobate substrates. The combination of optical, mechanical and electrical elements will make lithium niobate a great potential material for optical MEMS applications.</p> / Thesis / Master of Applied Science (MASc)

The demand for bandwidth is increasing vigorously. Thus wired network is using fiber optic telephone line instead of coaxial cable. The concept of Fiber to the Home (FTTH) is really coming into picture. Few countries like Japan, Korea etc are leading in this technology. But now the major challenge is how to provide the high speed internet connection wirelessly. Thus the change is to integrate the wireless and optical fiber communication. / Wireless Optical Communication