Este trabalho propõe uma extensão do método de propagação de feixe (BPM - Beam Propagation Method) para a análise de guias de ondas ópticos e acopladores baseados em materiais não-lineares do tipo Kerr. Este método se destina à investigação de estruturas onde a utilização da equação escalar de Helmholtz (EEH) em seu limite paraxial não mais se aplica. Os métodos desenvolvidos para este fim são denominados na literatura como métodos de propagação de feixe de ângulo largo. O formalismo aqui desenvolvido é baseado na técnica das diferenças finitas e nos esquemas de Crank-Nicholson (CN) e Douglas generalizado (GD). Estes esquemas apresentam como característica o fato de apresentarem um erro de truncamento em relação ao passo de discretização transversal, &#916x, proporcional a O(&#916x2) para o primeiro e O(&#916x4). A convergência do método em ambos esquemas é otimizada pela utilização de um algoritmo interativo para a correção do campo no meio não-linear. O formalismo de ângulo largo é obtido pela expansão da EEH para os esquemas CN e GD em termos de polinômios aproximantes de Padé de ordem (1,0) e (1,1) para CN e GD, e (2,2) e (3,3) para CN. Os aproximantes de ordem superior a (1,1) apresentam sérios problemas de estabilidade. Este problema é eliminado pela rotação dos aproximantes no plano complexo. Duas condições de contorno nos extremos da janela computacional são também investigadas: 1) (TBC - Transparent Boundary Condition) e 2) condição de contorno absorvente (TAB - Transparent Absorbing Boundary). Estas condições de contorno possuem a facilidade de evitar que reflexões indesejáveis sejam transmitidas para dentro da janela computacional. Um estudo comparativo da influência destas condições de contorno na solução de guias de ondas ópticos não-lineares é também abordada neste trabalho. / This work introduces an extension of the beam propagation method (BPM) for the analysis of optical waveguides and couplers based on Kerr-type nonlinear materials. This method is intended for the investigation of structures where the paraxial scalar Helmholtz equation (EEH) no longer holds. The numerical methods developed for this situation are known in the literature as wide-angle beam propagation methods. The formulation developed in this work is based on finite differences and on the Crank-Nicholson (CN) and Generalized Douglas (GD) schemes. These schemes are characterized by a truncation error with respect to the transverse discretization step, &#916x, proporcional to O(&#916x2) for the CN and to O(&#916x4) for the GD scheme. The convergence of the method for both schemes is optimized by the application of an iterative algorithm for the correction of the field in the nonlinear medium. The wide-angle formalism is obtained by the expansion of the EEH for the CN and GD schemes in terms of Padé approximant polynomials. The expansions addressed in this work utilize Padé approximants of order (1,0) and (1,1) for the CN and GD scheme, and (2,2) and (3,3) for the CN scheme. Approximants orders higher than (1,1) show serious stability problems. This problem is circumvented by rotating the approximants in the complex plane. Two boundary conditions on the edge of the computational window are also investigated: 1) transparent boundary condition (TBC) and 2) transparent absorbing boundary (TAB). These boundary conditions are necessary in order to avoid unwanted reflections back to computational domain. A comparative study of the influence of these boundary conditions on the solution of nonlinear optical waveguides is also addressed in this work.

Avec la croissance forte de ces dernières années des objets connectés les technologies de communication optique et radio voient davantage d’opportunités de s’associer et se combiner dans des technologies bas-couts Photoniques-Microondes (MWP). Les réseaux domestiques en sont un exemple. La bande millimétrique notamment, de 57GHz à 67GHz, est utilisé pour contenir les exigences des communications sans fils très haut-débit, néanmoins, la couverture de ces systèmes wireless est limitée en intérieur (indoor) essentiellement à une seule pièce, à la fois du fait de l’atténuation forte de l’atmosphère dans cette bande de fréquence, mais aussi de fait de l’absorption et de la réflexion des murs. Ainsi il nécessaire de déployer une infrastructure pour diffuser l’information au travers d’un système d’antennes distribuées. Les technologiques optiques et photoniques-microondes sont une des solutions envisagées. Les technologies MWP se sont également étendues et couvrent une gamme très large d’applications incluant les communications mobiles 5G, les analyses biomédicales, les communications courtes-distances (datacom), le traitement de signal par voie optique et les interconnexions dans les véhicules et aéronefs. Beaucoup de ces applications requièrent de la rapidité, de la bande-passante et une grande dynamique à la fois, en même temps de demander des dispositifs compacts, légers et à faible consommation. Le cout d’implémentation est de plus un critère essentiel à leur déploiement, en particulier dans l’environnement domestique ainsi que dans d’autres applications variées des technologies MWP.Ce travail de thèse vise ainsi le développement de composants photonique-microondes (MPW) intégrés en technologie BiCMOS ou Bipolaire SiGe/Si, à très bas coût, incluant les phototransistors bipolaires à hétérojonctions (HPT) SiGe/Si, les Diodes Electro-Luminescentes (LED) Si et SiGe, ainsi que l’intégration combinées des composants optoélectroniques et microondes, pour l’ensemble des applications impliquant des courtes longueurs d’ondes (de 750nm à 950nm typiquement).Ces travaux se concentrent ainsi sur les points suivants :La meilleure compréhension de phototransistors SiGe/Si latéraux et verticaux conçus dans une technologie HBT SiGe 80GHz de Telefunken GmbH. Nous traçons des conclusions sur les performances optimales du phototransistor. Les effets de photodétection du substrat et de la dispersion spatiale des flux de porteurs sont analysés expérimentalement. Cette étude aide à développer des règles de dessin pour améliorer les performances fréquentielles du phototransistor HPT pour les applications visées.Dans l’objectif de développer de futures interconnexions intra- et inter- puces, nous concevons des lignes de transmissions faibles-pertes et des guides d’ondes optiques polymères sur Silicium faible résistivité. Il s’agit d’une étape afin d’envisager des plateformes Silicium dans lesquelles les HPT SiGe pourront potentiellement être intégrés de manière performante à très bas coût avec d’autres structures telles que des lasers à émission par la surface (VCSEL), afin de construire un transpondeur optique complet sur une interface Silicium. Le polymère est utilisé comme une interface diélectrique entre les lignes de transmission et le substrat, pour les interconnexions électriques, et pour définir le gain du guide d’onde optique dans les interconnexions optiques.La conception, la fabrication et la caractérisation du premier lien photonique-microonde sur puce Silicium sont menées en se basant sur la même technologie HBT SiGe 80GHz de Telefunken dans la gamme de longueur d’onde 0,65µm-0,85µm. Ce lien optique complétement intégré combine des LEDS Silicium en régime d’avalanche (Si Av LED), des guides d’ondes optiques Nitrure et Silice ainsi qu’un phototransistor SiGe. Un tel dispositif pourrait permettre d’accueillir à l’avenir des communications sur-puce, de systèmes micro-fluidiques et des applications d’analyse biochimiques / With the recent explosive growth of connected objects, for example in Home Area Networks, the wireless and optical communication technologies see more opportunity to merge with low cost MicroWave Photonic (MWP) technologies. Millimeter frequency band from 57GHz to 67GHz is used to accommodate the very high speed wireless data communication requirements. However, the coverage distance of these wireless systems is limited to few meters (10m). The propagation is then limiting to a single room mostly, due to both the high propagation attenuation of signals in this frequency range and to the wall absorption and reflections. Therefore, an infrastructure is needed to lead the signal to the distributed antennas configuration through MWP technology. Moreover, MWP technology has recently extended to address a considerable number of novel applications including 5G mobile communication, biomedical analysis, Datacom, optical signal processing and for interconnection in vehicles and airplanes. Many of these application areas also demand high speed, bandwidth and dynamic range at the same time they require devices that are small, light and low power consuming. Furthermore, implementation cost is a key consideration for the deployment of such MWP systems in home environment and various integrated MWP application.This PhD deals with very cheap, Bipolar or BiCMOS integrated SiGe/Si MWP devices such as SiGe HPTs, Si LEDs and SiGe LEDs, and focused on the combined integration of mm wave and optoelectronic devices for various applications involving short wavelength links (750nm to 950nm).This research focused on the study of the following points:The better understanding of vertical and lateral illuminated SiGe phototransistors designed in a 80 GHz Telefunken GmbH SiGe HBT technology. We draw conclusions on the optimal performances of the phototransistor. The light sensitive Si substrate and two-dimensional carrier flow effects on SiGe phototransistor performance are investigated. This study helps to derive design rules to improve frequency behavior of the HPT for the targeted applications.For future intra /inter chip hybrid interconnections, we design polymer based low loss microwave transmission lines and optical waveguides on low resistive silicon substrate. It is a step to envisage further Silicon based platforms where SiGe HPT could be integrated at ultra-low cost and high performances with other structures such high-speed VCSEL to build up a complete optical transceiver on a Silicon optical interposer. The polymer is used as dielectric interface between the line and the substrate for electrical interconnections and to design the core and cladding of the optical waveguide.The design, fabrication and characterization of the first on-chip microwave photonic links at mid infrared wavelength (0.65-0.85μm) based on 80 GHz Telefunken GmbH SiGe HBT technological processes. The full optical link combines Silicon Avalanche based Light Emitting Devices (Si Av LEDs), silicon nitride based waveguides and SiGe HPT. Such device could permit hosting microfluidic systems, on chip data communication and bio-chemical analysis applications

Le développement de sources moyen infrarouge compactes et accordables dans les gammes de transmission de l’atmosphère présente un intérêt majeur dans les secteurs de la défense et de la sécurité. Les sources paramétriques à quasi-accord de phase en configuration guidée sont prometteuses pour gagner en compacité puisque l’on réduit la puissance de pompe nécessaire par rapport aux sources « massives ». Le premier axe de la thèse consiste à étudier des guides d’onde en arséniure de gallium périodiquement orientés (OP-GaAs) adaptés à un pompage par laser fibré et à des puissances relativement élevées. Le second vise à étudier de façon novatrice la possibilité d’intégrer dans un composant monolithique une diode laser en matériaux antimoniures avec un convertisseur de fréquence en antimoniure de gallium (GaSb). L’enjeu dans les deux cas est de réduire au maximum les pertes à la propagation dans ces guides d’onde pour exploiter pleinement leurs propriétés non-linéaires.Ce travail de thèse a permis de modéliser des structures de guides d’onde ambitieuses pour réduire les pertes, de développer les briques technologiques nécessaires à la fabrication de guides d’onde OP-semi-conducteur faibles pertes et de faire de premières caractérisations de ces composants dans le moyen-infrarouge. Les performances de guides d’onde GaAs ruban enterrés ou non ont pu être comparées, donnant une réduction des pertes d’un facteur trois avec des rubans enterrés. Plusieurs générations de guides d’onde GaSb ont vu le jour, et montrent des performances à l’état de l’art des structures en GaAs. En conséquence, diverses solutions ont été explorées pour intégrer une diode laser en matériaux antimoniures avec le guide d’onde convertisseur de fréquence. / The development of compact and tunable mid-infrared laser sources in the atmospheric transmission windows presents a major interest for several security and defense applications. Quasi-phase-matched parametric sources in guided wave configuration are promising solutions to enhance compactness, because of the reduction in pump power requirements with respect to bulk devices.The first axis of this thesis consists in studying orientation-patterned gallium arsenide (OP-GaAs) waveguides, adapted to fiber laser pumping and to relatively high pump power. The second axis is devoted to the original idea of integrating an antimonide based laser diode with a gallium antimonide (GaSb) frequency converter in a monolithic component. The goal in both cases is to minimize propagation losses in those waveguides to exploit the whole potential of their non-linear properties.This work led to model ambitious low-loss waveguides structures, to develop the technological fabrication steps necessary for OP-semiconductor waveguides manufacturing, and to characterize these components in the mid-infrared. The first buried ridge GaAs waveguide structure has been compared to the ridge one, giving a reduction of a factor three in the propagation losses. Several generations of GaSb waveguides have come forward, with constant losses improvement and reach GaAs state-of-the-art performances. Lastly, multiple solutions have been explored in order to integrate an antimonide-based laser diode with the frequency converter waveguide.

Orientadores: Leandro Tiago Manera, Arismar Cerqueira Sodré Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-27T14:09:44Z (GMT). No. of bitstreams: 1 NascimentoJunior_AdrianoRicardo_M.pdf: 49523846 bytes, checksum: 938b4d8587e112835bf6e0988731ba04 (MD5) Previous issue date: 2015 / Resumo: Neste trabalho foram fabricados microrressonadores em anel com alto fator de qualidade utilizando filmes de nitreto de silício (SixNy) depositados a baixa temperatura (20 °C) utilizando a técnica de deposição ECR-CVD (Deposição em Fase Vapor por Resonância Ciclotrônica do Elétron). Graças à alta não linearidade do SixNy, tais filmes têm sido recentemente usados para aplicações em óptica não linear como a geração de pentes de frequência na banda C de telecomunicações. Para tais aplicações, o guia de onda do dispositivo deve possuir um ponto de dispersão nula no centro da banda C, necessitando de uma grande área. Infelizmente, filmes espessos de nitreto de silício (>400 nm) possuem um alto stress responsável pela ocorrência de rachaduras catastróficas no filme que reduzem drasticamente a eficiência do dispositivo. Utilizando simulações numéricas, demonstrou-se que para valores de índice de refração (n) maiores que 2, a área do guia de onda com zero dispersão em ? = 1,55 ?m é consideravelmente reduzida, necessitando assim de uma menor espessura de filme. Foi obtido um filme de SixNy rico em Si, com índice de refração igual a 2, alta taxa de deposição, baixa concentração de hidrogênio e uma rugosidade média de somente 0,52 nm (4,2 nm de desvio padrão). Devido à baixa temperatura da técnica de deposição empregada, não foi observado traços de stress no filme, permitindo a obtenção de uma espessura de 730 nm utilizando uma única etapa de deposição. Os microrressonadores ópticos fabricados com raios de 60 e 120 ?m apresentaram um FSR (Free Spectral Range) equidistante em toda a banda C e um fator de qualidade de 7,2x10^3 foi obtido experimentalmente. Tais resultados demonstraram a alta eficiência dos dispositivos fabricados com o filme de SixNy desenvolvido e sua promissora aplicação para óptica não linear na banda C de telecomunicações / Abstract: Silicon nitride (SixNy) films deposited by low-pressure electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-CVD) at room temperature are proposed for fabrication of microring resonators with high Q-factor. Due to the high silicon nitride nonlinearity, these films recently have also been used for nonlinear optics applications in the telecommunications C-band. For nonlinear applications such as the generation of frequency combs, the waveguide needs a zero dispersion point in the middle of C-band, requesting large waveguide area. Unfortunately, these thick SixNy films (>400 nm) have high stress and suffer from catastrophic cracking, which reduces the device efficiency. Using numerical simulations it was demonstrated that for refractive index (n) values greater than 2, the area of the waveguide with zero dispersion point at ? = 1.55 ?m is greatly reduced. A Si-rich silicon nitride layer with refractive index of 2, high deposition rate, low hydrogen concentration and roughness average of 0.52 nm with standard deviation of 4.2 nm was obtained. Due to the low temperature deposition, no thermal stress was observed in the SixNy film, allowing a thickness of 730 nm obtained with only one deposition step. After experimental measurements, microring resonators having a radius of 60 and 120 ?m, presented an equidistant Free Spectral Range and a Q-factor of 7.2x10^3 was achieved, showing the high efficiency of the device and their promising application in nonlinear effects in the telecommunication C-band / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Cette thèse s'articule autour de l'étude de la cohérence de la lumière produite à partir de sources de paires de photons intriqués et de micro-lasers. Nous avons produit et manipulé des états photoniques intriqués, et conduit des investigations à la fois fondamentales et appliquées. Les deux études menées sur les aspects fondamentaux de la non localité avaient pour but de relaxer partiellement deux contraintes sur lesquelles s'appuie l'inégalité de Bell standard en vue d'applications à la cryptographie quantique. Ainsi, en collaboration avec l'Université de Genève, nous avons redéfini la notion de localité en prenant en compte les influences sur les mesures de corrélations des choix des configurations expérimentales et d'une efficacité globale de détection limitée. Cela a permis de définir des inégalités de Bell généralisées et les violations expérimentales qui en découlent permettent d'attester de la non localité des états quantiques observés. Nous avons aussi étudié et mis en place une solution expérimentale autorisant l'émission de photons intriqués dans des pairs de canaux télécoms pour la cryptographie quantique. Nous avons montré la préservation de l'intrication sur 150 km et obtenu des débits records en comparaison avec les réalisations similaires. Enfin, nous avons étudié les propriétés de l’émission de lasers à semi-conducteurs aux dimensions réduites. L’émission de ces composants microscopiques s'accompagne de grandes fluctuations en intensité lorsque ceux-ci sont pompés en-dessous du seuil laser. Cette étude a permis de mieux comprendre comment se construit la cohérence laser dans ces systèmes. / In this thesis we study the coherence of light emitted by entangled photon-pair sources and micro-lasers. We have generated an manipulated entangled photonic states and investigated both fundamental (non locality) and applied (quantum cryptography) research directions. The objective of two fundamental studies on non locality was to partially relax the strong assumptions on which standard Bell tests rely. To this end, we redefined, in collaboration with the University of Geneva, the formalism of locality taking into account the influence, on correlation measurements, of the freedom of choice (in the basis settings) and of the limitation of the overall detection efficiency. Both assumptions allow devising generalized Bell inequalities whose experimental violations indicate that we can still attest for non locality for the observed states. In addition, we have studied and realized an experimental setup allowing to distribute entangled photon pairs in paired telecom channels for high bit rate quantum cryptography. We have shown that entanglement is preserved over a distance of 150 km with record rates for similar realizations, by mimicking classical network solutions exploiting, in an optimal fashion, the capacity of an optical fiber link via dense spectral multiplexing. Finally, we have studied the properties of light emitted by semiconductor lasers showing reduced dimensionality. This micro-lasers actually provide output light under high intensity fluctuations when they are pumped below the threshold. Their study allowed to refine our understanding on how the coherence builds up in these systems as the cavity is filled with photons.

The aim of the present work was to design and fabricate all purpose, positioning-tolerant and efficient interconnects between single-mode fibers and integrated waveguides out of polymers. The developed structures are part of the optical packaging of integrated optical chips. Integrated optics have gathered tremendous interest throughout recent years from research as well as from the industry, and most likely the demand will further grow in the future. Today’s trend is to establish optical data communication not only in far-distance transmission but also in end-user or so called fiber-to-home configurations, or, in the near future, also on board or even chip level. In addition, integrated optical sensors are gaining more and more importance. In the future, lab-on-a-chip systems may be able to simplify and accelerate analysis methods within health care or allow for a continuous monitoring of almost any environmental variable. All these applications call for robust optical packaging solutions. Many integrated optical chips are using a silicon-on-insulator design. Technologies which were originally intended for the manufacturing of integrated circuits can be utilized for the fabrication of such silicon-on-insulator chips. Point-of-care testing, which is a considerable part of bio-sensing, in some cases only allows the use of disposable transducer elements. The fabrication of these transducers, also including almost all other system parts, may be possible using polymers. Alternative fabrication methods like nanoimprint lithography can be applied for the patterning of polymers. With these, the extension of already known working principles or even entirely new device architectures become feasible for mass production. The direct patterning of polymers by means of nanoimprint was used to fabricate interconnects for integrated waveguides. In contrast to conventional lithography approaches, where a patterned resist layer is used as a masking layer for subsequent process steps, direct patterning allows the immediate use of the structures as functional elements. Firstly, nanoimprint allows diffraction-unlimited patterning with nanometer resolutions as well as the replication of complex three-dimensional patterns. These unique properties were used within this work to pattern shallow gratings atop an integrated waveguide within only one single manufacturing step. The gratings are used as coupling elements and can be utilized either to couple light from external elements to the chip or vice versa. Considerations regarding the optical effects on single-mode polymer waveguides as well as grating couplers were obtained from simulation. They are specific to the chosen design and the used polymer and cannot be found elsewhere so far. Compared to similar designs and fabrication strategies proposed in literature, the ones followed here allow for a higher efficiency. The dimensions and process windows obtained from simulation did serve as a basis for the subsequent fabrication of the grating couplers. All steps which are necessary to turn the calculated design into reality, ranging from master fabrication, to working mold cast and imprint, are shown in detail. The use of a working mold strategy is of crucial importance for the fabrication process and is discussed in detail. The use of a working mold preserves a costly master and further allows for a cost-efficient production. Parameters which are relevant for the production as well as for the final polymer patterns were analyzed and discussed. On the basis of the obtained data, a process optimization was performed. The optical characterization was also part of the presented work. A comparison with the results obtained from simulation is included and additional effects were revealed. Most of them may be subject to further improvement in future designs. In summary, the present work contributes to the field of optical packaging. It shows a viable route for the design and fabrication of interconnects of single-mode polymer waveguides. The presented design can be used as a building block which can be placed at almost any positions within an integrated optical chip. The fabrication method includes a minimum number of process steps and is still able to increase performance compared to similar approaches. Moreover, all process steps allow for scaling and are potential candidates for mass production.

No description available.

We are reporting on a study of the near-field sensitivity and resolution of a metal-dielectric probe (MDP). The propagation of the electromagnetic field across the probe was studied experimentally by means of time-domain terahertz spectroscopy and numerically simulated by CST MicroWave Studio 2008. Several localised areas at the probe end facet were distinguished and showed to be sensitive to the local dielectric properties and local anisotropy of the sample. Contrast and sensitivity measurements were conducted in several configurations of a MDP; the results were confirmed by simulations. The acquired data were analysed by using singular value decomposition that enabled separating independent physical phenomena in the measured datasets and filtering external disturbances out of the signal. Independent components corresponding to the changes in the output terahertz pulse upon varying the probe-sample distance and reflecting the local anisotropy in a ferroelectric barium titanate (BaTiO3) crystal were extracted and identified. The domain structure with characteristic dimensions of about 5 um was resolved during imaging experiments on the ferroelectric BaTiO3 sample, i.e. the resolved structures were ten times smaller than the characteristic dimensions of the end facet of the probe and forty times smaller than...

Optical connectivity has the potential to outperform copper-based TSVs in terms of bandwidth at the cost of more complexity due to the required electro-optical and opto-electrical conversion. The continuously increasing demand for higher bandwidth pushes the breakeven point for a profitable operation to shorter distances. To integrate an optical communication network in a 3D-chip-stack optical through-silicon vertical VIAs (TSV) are required. While the necessary effort for the electrical/optical and vice versa conversion makes it hard to envision an on-chip optical interconnect, a chip-to-chip optical link appears practicable. In general, the interposer offers the potential advantage to realize electro-optical transceivers on affordable expense by specific, but not necessarily CMOS technology. We investigated the realization and characterization of optical interconnects as a polymer based waveguide in high aspect ratio (HAR) TSVs proved on waferlevel. To guide the optical field inside a TSV as optical-waveguide or fiber, its core has to have a higher refractive index than the surrounding material. Comparing different material / technology options it turned out that thermal grown silicon dioxide (SiO2) is a perfect candidate for the cladding (nSiO2 = 1.4525 at 850 nm). In combination with SiO2 as the adjacent polymer layer, the negative resist SU-8 is very well suited as waveguide material (nSU-8 = 1.56) for the core. Here, we present the fabrication of an optical polymer based multimode waveguide in TSVs proved on waferlevel using SU-8 as core and SiO2 as cladding. The process resulted in a defect-free filling of waveguide TSVs with SU-8 core and SiO2 cladding up to aspect ratio (AR) 20:1 and losses less than 3 dB.

This paper describes simulation, technology- and process development for the manufacturing of single mode polymeric waveguides by photolithography. Simulations for single mode operation in O- and C-band are carried out. Waveguides are directly patterned with UV-photolithography using Ormocere®-material. Fiber to waveguide coupling and near field are characterized.