Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-07-13T22:58:20Z No. of bitstreams: 1 JoãoMC_DISSERT.pdf: 1741418 bytes, checksum: 13c15c64738df641ff1a1cadad54fa09 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-18T15:08:39Z (GMT) No. of bitstreams: 1 JoãoMC_DISSERT.pdf: 1741418 bytes, checksum: 13c15c64738df641ff1a1cadad54fa09 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-18T15:09:03Z (GMT) No. of bitstreams: 1 JoãoMC_DISSERT.pdf: 1741418 bytes, checksum: 13c15c64738df641ff1a1cadad54fa09 (MD5) / Made available in DSpace on 2017-07-18T15:10:18Z (GMT). No. of bitstreams: 1 JoãoMC_DISSERT.pdf: 1741418 bytes, checksum: 13c15c64738df641ff1a1cadad54fa09 (MD5) Previous issue date: 2014-11-07 / In this work, it is analyzed two applications involving optical fiber. In the first application, a new design of an optical fiber coupler composed by two and three cores from a fiber with step index is proposed and analyzed using a vector formulation based on finite element applied in conjunction with genetic algorithm (GA). The fiber is made with pure silica and silica doped with germanium and it is composed by two and three identical cores separated by distance d. The proposed structure has a very simple geometry, and each fiber that composed the coupler is obtained by inclusion of a very small air hole at the core of each conventional step index fibers. Next, optical fiber composed by photonic quasi-crystals, through a quasi-periodic and symmetric matrix, is analyzed using the finite element method, applied in conjunction with perfectly matched layers of type cylindrical. The structure is composed of germanium-doped silica and it is originates from twelve distributions of air holes arranged symmetrically with a defect caused by the absence of central air hole / Neste trabalho, serão analizadas duas aplicações envolvendo fibra óptica. Na primeira aplicação um novo projeto de um acoplador de fibra óptica constituída por dois e três núcleos a partir de uma fibra com índice degrau é proposta e analisada através de uma formulação vetorial baseada em elementos finitos aplicada em conjunto com o Algoritmo Genético (GA).A fibra é feita desílica pura e sílica dopada com germânio e contém dois e três núcleos idênticosseparados por umadistância d. A estrutura proposta apresenta uma geometria bastante simples, ecada fibra que compõe o acoplador é obtida através da inclusão de um buraco de ar muito pequeno no núcleo de cada uma das fibras de índice degrau convencional. Na segunda aplicação, fibras ópticas constituídas por quase cristais fotônicos, através de uma matriz quase periódica e simétrica é analisada através do método dos elementos finitos, aplicado em conjunto com camadas perfeitamente casadas do tipo cilíndricas. A estrutura é composta por sílica dopada com germânio e é originada a partir de doze distribuições de buracos de ar organizados simetricamente com um defeito provocado pela ausência do buraco de ar central / 2017-07-13

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Duas contribuiÃÃes caracteristicamente distintas, nÃo obstante correlacionÃveis num mesmo sistema de telecomunicaÃÃo, sÃo apresentadas. A primeira versa sobre antenas ressoadoras constituÃdas por novas cerÃmicas dielÃtricas à base de Fe2O3. Os materiais desenvolvidos foram caracterizados na faixa de micro-ondas. Tratam-se de dielÃtricos com baixa permissividade relativa, baixa tangente de perda, e, no caso das amostras monofÃsicas, com coeficiente de temperatura na frequÃncia de ressonÃncia negativo. Posteriormente, as antenas ressoadoras dielÃtricas de geometria cilÃndrica (CDRAs) suportadas em plano de terra retangular e alimentadas por sonda monopolar sÃo analisadas segundo critÃrios de desempenho de irradiaÃÃo, quais sejam: frequÃncia de ressonÃncia, impedÃncia de entrada, largura de banda e padrÃes de irradiaÃÃo. AlÃm de experimentaÃÃo, o seu estudo envolveu procedimento computacional, no que foi promovida a comparaÃÃo de resultados. O mÃtodo dos elementos finitos, no qual està baseado o programa comercial empregado, foi utilizado para anÃlise destas antenas. Resulta que para maiores valores de permissividade relativa de uma amostra, menores sÃo a frequÃncia em que a mesma ressoa e a sua largura de banda. Ainda, foi observado satisfatÃrio casamento de impedÃncia e padrÃes de irradiaÃÃo "broadside", o que candidata os novos materiais desenvolvidos a esta importante aplicaÃÃo. Adicionalmente, mediante empilhamento dos protÃtipos monofÃsicos examinados, foi verificada a remodelagem da largura de banda em relaÃÃo Ãs contrapartidas individuais, provavelmente devido à excitaÃÃo de modos de ordem elevada das CDRAs. A segunda contribuiÃÃo està enfocada no contexto dos guias de ondas dielÃtricos operando em frequÃncias Ãpticas. Neste cenÃrio, sÃo investigados acopladores refletores de Bragg a fibra (FBGCs), estruturas resultantes da combinaÃÃo de dois dispositivos reconhecidamente versÃteis e de ampla aplicaÃÃo: redes de Bragg e acopladores direcionais. Foram apreciados dois estudos de caso numÃricos nos quais se fez promover a interaÃÃo de sinais Ãpticos com as estruturas propostas. Na medida em que descreve com satisfatÃria precisÃo as propriedades Ãpticas dos dispositivos de interesse, o modelo matemÃtico empregado à baseado na teoria dos modos acoplados. O tratamento numÃrico à realizado mediante codificaÃÃo, em linguagem de programaÃÃo FORTRAN, de um algoritmo preditivo-corretor. Considerando regimes pulsados em termos da potÃncia operacional, o problema foi analisado no domÃnio da frequÃncia e, sobretudo, no domÃnio do tempo. Em condiÃÃes especÃficas, a possibilidade de realizaÃÃo da extraÃÃo, reconfiguraÃÃo e comutaÃÃo de pulsos, exemplos de funÃÃes essenciais ao processamento totalmente Ãptico, reforÃam a importÃncia de tais estruturas hÃbridas. / Two heterogeneous contributions to modern communication systems â although fully possible to be correlated â are presented. The first one deals with resonant antennas consisting of new dielectric ceramics based on Fe2O3. These materials characterized at microwave frequency range possess low relative permittivity, low loss tangent and, concerned with the monophasic samples, negative temperature coefficient of resonant frequency. Subsequently, the cylindrical dielectric resonator antennas (CDRAs) supported on rectangular ground plane and fed by monopole are analyzed according to the following radiation performance criteria: resonant frequency, input impedance, bandwidth and radiation patterns. Besides experimentation, the study involved computational procedure, so that the results of both can be compared. A commercial software based on the finite element method was employed to examine the CDRAs. It follows that as higher is the permittivity of a material, the lower are the frequency at which it resonates as well as its bandwidth. Satisfactory impedance matching and broadside radiation patterns are observed, what enables the materials investigated to this relevant application. Additionally, the stacking of the monophasic CDRAs prototypes resulted in bandwidth enhancement, presumably due to their excited high order modes. The second contribution focuses on dielectric waveguides operating at optical frequencies, being fiber Bragg grating couplers (FBGCs) investigated in this scenario. Indeed, they result from a combination of two versatile and widely applied devices: fiber Bragg gratings and directional couplers. Two numerical case studies related to the interaction between optical signals and structures were performed. The theoretical model observed is based on the coupled mode theory since it provides a satisfactorily accurate description of the devices optical properties. By the way, the theoretical model is coded in FORTRAN programming language according to a predictor-corrector algorithm. In terms of operational power levels, analyses are carried out in frequency and (mainly) time domains. Under specific conditions, the capability of the extraction, reshaping and switching of pulses â examples of essential functions for all-optical processing â reinforces the importance of such hybrid structures.

O incessante aumento do volume de informações produzido por uma sociedade cada vez mais informatizada tem elevado drasticamente os requisitos quanto ao desenvolvimento de dispositivos capazes de suportar velocidades de operação cada vez mais elevadas em tamanhos cada vez mais reduzidos. No entanto, a contínua redução do tamanho desses dispositivos, celebrado através da lei de Moore, também produz um indesejável aumento na produção de calor durante a operação dos mesmos, comprometendo seu desempenho global. Uma alternativa promissora para aliviar, ou mesmo superar, estas limitações é oferecida pelos dispositivos ópticos integrados. No entanto, todo esse avanço esbarrava no fato de que as dimensões de tais dispositivos estavam restringidas fundamentalmente ao que é largamente conhecido como limite de difração (LD). Uma maneira de contornar essa limitação é obtida através da utilização de Plásmon Poláritons de Superfície, ou SPPs, que, de maneira simplificada, são ondas que se propagam ao longo da superfície de um condutor depositado sobre um dielétrico. Estas são essencialmente ondas de luz que são localizadas na superfície por causa de sua interação com os elétrons livres do condutor. Nesta interação, os elétrons livres respondem coletivamente oscilando em ressonância com a onda de luz. No presente trabalho, o fenômeno de geração de SPPs é estudado teoricamente e aplicado na modelagem de diversas estruturas de interesse científico e tecnológico, tais como acopladores direcionais e ressoadores. O objetivo principal é a obtenção de estruturas capazes de proporcionar propagação de SPPs por longas distâncias, permitindo, assim, estender ainda mais o leque de possíveis aplicações. As estruturas são investigadas prioritariamente no COMSOL Multiphysics, um aplicativo baseado em elementos finitos que permite solução vetorial de problemas eletromagnéticos. Os resultados obtidos até o momento permitem afirmar que o conceito de SPP de longa distância (long range SPP, LRSPP) podem ser aplicados com sucesso a estruturas geometricamente complexas como os ressoadores em anel e acopladores direcionais. / The continuous growth of knowledge produced by a society with increasing access to information technologies has demanded the development of communication devices capable of supporting high processing speeds at more and more reduced sizes. Nevertheless, the continuous reduction of the size of these devices, celebrated by the Moore\'s law, has also produced an undesirable increase of heat produced during the operation of the device itself, compromising its overall performance. A promising alternative to alleviate, or even overcome, these limitations has been offered by photonic integrated circuits. However, all the advance of photonic devices was restricted to what is known as diffraction limit. A fascinating way of circumventing this limit is now available to the scientific community, and consists in the generation of Surface Plasmon Polariton (SPP) waves. In a simplified manner, SPP waves are waves that propagate along a metal/dielectric interface. These waves are essentially localized at the metal/dielectric interface because of the interaction of light with free electrons of the metal. In this interaction, the free electrons respond collectively and oscillate resonantly with the incident light. In the present work, the phenomenon of SPP generation is theoretically investigated and applied to the modeling of several structures, such as directional couplers and resonators. The primary goal of this work is to design structures capable propagating SPP waves for long distances, known as long range SPP (LRSPP). The structures are investigated mostly with COMSOL Multiphysics, a finite elements based software that allows for the vectorial solution of electromagnetic problems. The results obtained so far are extremely encouraging, and prove that the LRSPP concept can be successfully applied to geometrically complex structures, such as couplers and ring resonators.

[EN] Microwave photonics (MWP) is a well-established research field that investigates the use of photonic technologies to generate, distribute, process and analyze RF waveforms in the optical domain. Despite its great potential to solve long-standing problems faced by both the microwave and electronics industries, MWP systems are bulky, expensive and consume a lot of power. Integrated microwave photonics (IMWP) is an emerging area of research that promises to alleviate most of these drawbacks through the use of photonic integrated circuits (PIC). In this work, we have aimed at further closing the gap between the worlds of MWP and integrated optics. In particular, we have focused on the design and experimental characterization of PICs with reconfigurable, ring-assisted Mach-Zehnder interferometer filters (RAMZI), and demonstrated its potential use in different IMWP applications. These filters consist of a symmetric MZI loaded with ring resonators, which are coupled to the MZI branches by different optical couplers. The contributions of this thesis can be split into two sections. In the first one, we demonstrate integrated optical couplers and reflectors with variable power splitting and reflections ratios. These exploit the well-known properties of tapered multimode interference couplers (MMI), and their inherent robustness makes them highly suitable for the implementation of both RAMZI and reflective filters. Besides, we study in detail the impact of manufacturing deviations in the performance of a 4x4 MMI-based 90º hybrid, which is a fundamental building block in coherent optical communication systems. In the second section, we demonstrate the use of integrated RAMZI filters for three different IMWP applications, including instantaneous frequency measurement (IFM), direct detection of frequency-modulated signals in a MWP link, as well as in tunable, coherent MWP filters. A theoretical analysis of the limits and trade-offs that exist in photonics-based IFM systems is also provided. Even though these are early proof-of-concept experiments, we hope that further technological developments in the field will finally turn MWP into a commercial reality. / [ES] La fotónica de microondas (MWP) es un campo de investigación que estudia el uso de tecnologías ópticas para generar, distribuir, procesar y analizar señales de RF. A pesar de su gran potencial para resolver algunos de los problemas a los que se enfrentan las industrias electrónica y de microondas, estos sistemas son voluminosos, caros y consumen mucha potencia. La fotónica de microondas integrada (IMWP) es un área emergente que promete solucionar todos estos inconvenientes a través de la utilización de circuitos ópticos integrados (PIC). En esta tesis, hemos pretendido avanzar un poco más en el acercamiento entre estas dos disciplinas. En concreto, nos hemos centrado en el diseño y caracterización experimental de PICs con filtros reconfigurables basados en interferómetros Mach-Zehnder cargados con anillos (RAMZI), y demostrado su potencial uso en diferentes aplicaciones de IMWP. Los filtros RAMZI están hecho básicamente de un MZI simétrico cargado con anillos, los cuales a su vez se acoplan a las ramas del interferómetro a través de distintos acopladores ópticos. Las contribuciones de este trabajo se pueden dividir en dos partes. En la primera, hemos demostrado acopladores y reflectores ópticos integrados con coeficientes de acoplo y reflexión variables. Éstos explotan las propiedades de los acopladores por interferencia multimodal (MMI), y su robustez les hace muy atractivos para la implementación de filtros RAMZI y de tipo reflectivo. Además, hemos analizado el impacto que las tolerancias de fabricación tienen en el rendimiento de un híbrido óptico de 90º basado en un MMI 4x4, el cual es un elemento fundamental en los sistemas de comunicaciones ópticas coherentes. En la segunda parte, hemos demostrado el uso de filtros RAMZI en tres aplicaciones distintas de IMWP. En concreto, hemos utilizado dichos filtros para implementar sistemas de medida de frecuencia instantánea (IFM), detección directa de señales moduladas en frecuencia para enlaces fotónicos, así como en filtros coherentes y sintonizables de MWP. También hemos desarrollado un análisis teórico de las limitaciones y problemas que existen en los sistemas IFM. A pesar de que todos los experimentos realizados han consistido en prototipos para una prueba de concepto, esperamos que futuros avances tecnológicos permitan que la fotónica de microondas se convierta algún día en una realidad comercial. / [CAT] La fotònica de microones (MWP) és un camp d'investigació que estudia l'ús de tecnologies òptiques per a generar, distribuir, processar y analitzar senyals de radiofreqüència. A pesar del seu gran potencial per a resoldre alguns dels problemes als que s'enfronten les indústries electrònica i de microones, estos sistemes son voluminosos, cars i consumixen molta potència. La fotònica de microones integrada (IMWP) és un àrea emergent que promet solucionar tots estos inconvenients a través de la utilització de circuits òptics integrats (PIC). En esta tesi, hem pretés avançar un poc més en l'acostament entre estes dos disciplines. En concret, ens hem centrat en el disseny i caracterització experimental de PICs amb filtres reconfigurables basats en interferòmetres Mach-Zehnder carregats amb anells (RAMZI), i demostrat el seu potencial en diferents aplicacions d' IMWP. Els filtres RAMZI estan fets bàsicament d'un MZI simètric carregat amb anells, els quals, al seu torn, s'acoblen a les branques del interferòmetre a través de distints acobladors òptics. Les contribucions d'este treball es poden dividir en dos parts. En la primera, hem demostrat acobladors i reflectors òptics integrats amb coeficients de transmissió i reflexió variables. Estos exploten les propietats dels acobladors per interferència multimodal (MMI), i la seua robustesa els fa molt atractius per a la implementació de filtres RAMZI i de tipo reflectiu. A més a més, hem analitzat l'impacte que les toleràncies de fabricació tenen en el rendiment d'un híbrid òptic de 90 graus basat en un MMI 4x4, el qual és un element fonamental en els sistemes de comunicacions òptiques coherents. En la segona part, hem demostrat l'ús de filtres RAMZI en tres aplicacions diferents de IMWP. En concret, hem utilitzat estos filtres per a implementar sistemes de mesura de freqüència instantània (IFM), detecció directa de senyals modulades en freqüència per a enllaços fotònics, així com en filtres coherents i sintonitzables de MWP. També hem desenvolupat una anàlisi teòrica de les limitacions i problemes que existixen en els sistemes IFM. A pesar de que tots els experiments realitzats han consistit en prototips per a una prova de concepte, esperem que futurs avanços tecnològics permeten que la fotònica de microones es convertisca algun dia en una realitat comercial. / Sánchez Fandiño, JA. (2016). Integrated Optical Filters for Microwave Photonic Applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/67690 / TESIS

Objective: To evaluate the long-term safety and performance of four different vibroplasty couplers (round window, oval window, CliP and Bell coupler) in combination with an active middle ear implant. Methods: This was a multicentre, prospective, long-term study including 5 German hospitals. Thirty adult subjects suffering from conductive or mixed hearing loss were initially enrolled for the study, 24 of these were included in the final analysis with up to 36 months of postsurgical follow-up data. Bone conduction and air conduction were measured pre- and postoperatively to evaluate safety. Postoperative aided sound field thresholds and Freiburger monosyllable word recognition scores were compared to unaided pre-implantation results to confirm performance. Additional speech tests compared postoperative unaided with aided results. To determine patient satisfaction, an established quality-of-life questionnaire developed for conventional hearing aid usage was administered to all subjects. Results: Mean postoperative bone conduction thresholds remained stable throughout the whole study period. Mean functional gain for all couplers investigated was 38.5 ± 11.4 dB HL (12 months) and 38.8 ± 12.5 dB HL (36 months). Mean word recognition scores at 65 dB SPL increased from 2.9% in the unaided by 64.2% to 67.1% in the aided situation. The mean postoperative speech reception in quiet (or 50% understanding of words in sentences) shows a speech intelligibility improvement at 36 months of 17.8 ± 12.4 dB SPL over the unaided condition. The signal-to-noise ratio (SNR) improved by 5.9 ± 7.2 dB SNR over the unaided condition. High subjective device satisfaction was reflected by the International Inventory for Hearing Aids scored very positively. Conclusion: A significant improvement was seen with all couplers, and audiological performance did not significantly differ between 12 and 36 months after surgery.

Objective: To evaluate the safety and effectiveness of round window (RW), oval window (OW), CliP and Bell couplers for use with an active middle ear implant. Methods: This is a multicenter, long-term, prospective trial with consecutive enrollment, involving 6 university hospitals in Germany. Bone conduction, air conduction, implant-aided warbletone thresholds and Freiburger monosyllable word recognition scores were compared with unaided preimplantation results in 28 moderate-to-profound hearing-impaired patients after 12 months of follow-up. All patients had previously undergone failed reconstruction surgeries (up to 5 or more). In a subset of patients, additional speech tests at 12 months postoperatively were used to compare the aided with the unaided condition after implantation with the processor switched off. An established quality-of-life questionnaire for hearing aids was used to determine patient satisfaction. Results: Postoperative bone conduction remained stable. Mean functional gain for all couplers was 37 dB HL (RW = 42 dB, OW = 35 dB, Bell = 38 dB, CliP = 27 dB). The mean postoperative Freiburger monosyllable score was 71% at 65 dB SPL. The postimplantation mean SRT 50 (speech reception in quiet for 50% understanding of words in sentences) improved on average by 23 dB over unaided testing and signal-to-noise ratios also improved in all patients. The International Outcome Inventory for Hearing Aids (IOI-HA) quality-of-life questionnaire was scored very positively by all patients. Conclusion: A significant improvement was seen with all couplers, and patients were satisfied with the device at 12 months postoperatively. These results demonstrate that an active implant is an advantage in achieving good hearing benefit in patients with prior failed reconstruction surgery.

By means of numerical simulations, the thesis aims at improvements in the understanding of light propagation in dielectric optical waveguides, with emphasis on nonreciprocal integrated magnetooptic devices. The results include: Proposal, implementation, and assessment of the WMM mode solver (Wave Matching Method) For waveguides with piecewise constant, rectangular permittivity profiles, the calculation of guided modes can be based on a local expansion into factorizing harmonic or exponential trial functions. A least squares expression for the mismatch in the continuity conditions at dielectric boundaries connects the fields on neighbouring regions. Minimization of this error allows to compute propagation constants and mode fields. The procedure has been implemented both for semivectorial and fully vectorial mode analysis. The piecewise defined trial fields are well suited to deal with field discontinuities or discontinuous derivatives. Numerical assessment shows excellent agreement with accepted previous results from other methods. The WMM turns out to be effective especially for structures described by only a few rectangles. It yields semianalytical mode field representations which are not restricted to a computational window. The fields are therefore perfectly suited for further processing, e.g. in the framework of various kinds of perturbation theory. Perturbational geometry tolerancing procedure Shifting the location of a dielectric boundary in the cross section of a waveguide with piecewise constant refractive index profile results in a permittivity perturbation in a layer along the discontinuity line. On the basis of these thin layer perturbations, perturbational expressions for the derivatives of the propagation constants with respect to geometry parameters are discussed. The approach provides direct access to wavelength dependences. Comparison with rigorously calculated data shows that the accuracy is sufficient to yield reasonable tolerance estimates for realistic integrated optical devices, at almost no extra computational cost. This perturbational approach allows to establish and to quantify guidelines for geometry tolerant devices. Numerical assessment of nonreciprocal wave propagation The coefficients of coupled mode theory for the magnetooptic permittivity contribution allow a classification of the influences of gyrotropy on guided wave propagation. For mirror symmetric waveguides, one identifies the dominant effects of TE phase shift, TM phase shift, and TE/TM polarization conversion, for polar, equatorial, and longitudinal magnetooptic configurations, respectively. Layered equatorial magnetooptic profiles lead to the well known phase shifters for TM modes. Analogously, sliced asymmetric polar magnetooptic profiles yield phase shifts for TE polarized modes. Simulations of rib waveguides with a magnetooptic domain lattice predict effects of the same order of magnitude as the phase shift for TM modes. Phase matching as a condition for complete polarization conversion in longitudinally magnetized waveguides can be realized with selected geometries of raised strip waveguides or embedded square waveguides. Based on coupled mode theory for hybrid fundamental modes, the analysis of the performance of such devices in an isolator setting includes birefringence, optical absorption, and an explicit perturbational evaluation of fabrication tolerances. A magnetooptic waveguide which is magnetized at a tilted angle may perform as a unidirectional polarization converter. The term specifies a device that converts TE to TM light for one direction of propagation, while it maintains the polarization for the opposite direction. A double layer setup with two magnetooptic films of opposite Faraday rotation is proposed and simulated. Designs of three waveguide couplers for applications as isolators/circulators and polarization splitters Three-guide couplers with multimode central waveguides allow for a remote coupling between the outer waveguides. While the power transfer is a truly multimode interference process, one can identify two different regimes where either two or three supermodes dominate the coupling behaviour. Numerical simulations show reasonable agreement between the main coupling features in planar an three dimensional devices. The specific form of the relevant modes suggests the design of integrated optical isolators and circulators. Both planar and three dimensional concepts are investigated. A radiatively coupled waveguide polarization splitter should be designed such that the entire dynamic range of the coupling length variations is exploited. This is easily possible with a three dimensional raised strip configuration. Combination of two magnetooptic unidirectional polarization converters and two radiatively coupled waveguide based polarization splitters leads to a concept for a polarization independent integrated four port circulator device. The simulation predicts a total length of about three millimeters.

Die chromatische Dispersion ist in optischen Übertragungssystemen mit Datenraten von 10 Gbit/s und darüber einer der Faktoren, der die Länge der Übertragungsstrecke limitiert. Der Hauptteil der chromatischen Dispersion wird in solchen Übertragungssystemen in der Regel durch Dispersionskompensationsfasern ausgeglichen. Aufgrund von z.B. Umwelteinflüssen kann allerdings auch eine sich zeitlich ändernde Dispersion auftreten. Zur Eliminierung dieser Restdispersion wurden unterschiedliche Ansätze wie abstimmbare Faser-Bragg-Gitter, Virtually-Imaged-Phased-Arrays und Delay-Line-Filter publiziert. Delay-Line-Filter, deren periodisches Übertragungsverhalten durch die Filterkoeffizienten bestimmt wird, wurden bereits als Ring-Resonatoren und kaskadierte Mach-Zehnder-Interferometer in integriert-optischer Technologie hergestellt. Integriert-optische Komponenten verursachen aufgrund der Ankopplung an die Fasern des Übertragungssystems hohe Einfügeverluste. Darüber hinaus treten hohe Wellenleiterverluste, polarisationsabhängige Verluste und Polarisationsmodendispersion auf. Daher wird in dieser Arbeit die Realisierung faseroptischer Delay-Line-Filter, die auf faseroptischen Schmelzkopplern und faseroptischen Gewichtungselementen basieren, untersucht. Aufgrund der geometrischen Längen der faseroptischen Schmelzkoppler und der Größe der Gewichtungselemente können solche Filter allerdings nur mit einer geringen Filterordnung und mit einer geringen Anzahl von Gewichtungselementen hergestellt werden. Um mit Filtern niedriger Ordnung eine möglichst effektive Kompensation der Restdispersion zu erzielen, ist zunächst eine sorgfältige Untersuchung der Filtereigenschaften und des Filterentwurfs erforderlich. Durch systematische Untersuchung des Verhaltens der Filterdispersion in Abhängigkeit der Filterkoeffizienten wurden in dieser Arbeit hierzu erstmalig einfache Entwurfsregeln aufgestellt, die für Filter beliebiger Filterordnung zu annähernd konstantem Dispersionsverlauf führen. Auf dieser Grundlage konnte ein faseroptisches Delay-Line-Filter realisiert werden, das auf zwei in Reihe geschalteten faseroptischen 3x3 Schmelzkopplern basiert. Die Dispersion dieses Filters ist in einem Bereich von 50 GHz um die Mitte einer Filterperiode herum annähernd konstant und kann in einem Bereich von +/-50 ps/nm durch ein einzelnes thermisches Gewichtungselement abgestimmt werden. Aufgrund der faseroptischen Realisierung kann die Komponente problemlos in optische Übertragungsstrecken integriert werden und verursacht dabei Einfügeverluste von lediglich 3 dB. In Übertragungsexperimenten bei Datenraten von 42,5 Gbit/s konnte gezeigt werden, dass das Filter in der Lage ist die Dispersionstoleranz des Systems annähernd zu verdoppeln. Dies gilt sowohl für die Kompensation eines einzelnen Kanals als auch für die simultane Kompensation mehrerer benachbarter Übertragungskanäle mit je 42,5 Gbit/s. / Chromatic dispersion is a limiting factor in fast optical networks with channel bit rates of 10 Gbit/s or higher. The main part of the dispersion is usually compensated by spans of dispersion compensating fiber that have a fixed dispersion value. But the residual dispersion caused by environmental changes or rerouting has to be compensated adaptively. To overcome the effects of residual dispersion several approaches like tunable fiber Bragg gratings, virtually imaged phased arrays and delay line filters can be found in literature. The use of delay line filters like cascaded ring-resonators, multi-cavity etalons and cascaded Mach-Zehnder interferometers, whose periodic transfer behavior is determined by their coefficients, have already been developed in planar-optics. These components cause insertion loss due to the coupling to the fibers. Furthermore they suffer from high waveguide loss, non-negligible polarization dependent loss and polarization mode dispersion. In this thesis the realization of tunable delay line filters based on fiberoptic couplers and fiberoptic weighting elements is investigated. Due to the size of these components the filters can be realized with a limited order and a limited number of weighting elements, only. To fulfill these requirements a careful investigation of the filter design is necessary. By systematically investigating the dispersion of the filter depending on the filter coefficients simple design rules for non-recursive delay line filters with approximately constant dispersion are figured out. That enables the realization of a fiberoptic delay line filter, based on two 3x3 couplers concatenated in series. The dispersion of this filter is constant in a bandwidth of about 50 GHz around the center of a period and can be tuned in a range of +/-50 ps/nm by changing one single weighting element. Due to its nature this device causes low loss and can be easily integrated in an optical transmission system. In experiments it was demonstrated that by adding this filter to a 42.5 Gb/s transmission system the +/- 55 ps/nm dispersion tolerance of the optical receiver can almost be doubled - either in a single channel as well as in a multi channel configuration with five adjacent 42.5 Gb/s channels.

This thesis presents an introduction to the design and simulation of a novel class of integrated photonic phased array switch elements. The main objective is to use nano-electromechanical (NEMS) based phase shifters of cascaded under-etched slot nanowires that are compact in size and require a small amount of power to operate them. The structure of the switch elements is organized such that it brings the phase shifting elements to the exterior sides of the photonic circuits. The transition slot couplers, used to interconnect the phase shifters, are designed to enable biasing one of the silicon beams of each phase shifter from an electrode located at the side of the phase shifter. The other silicon beam of each phase shifter is biased through the rest of the silicon structure of the switch element, which is taken as a ground. Phased array switch elements ranging from 2×2 up to 8×8 multiple-inputs/multiple-outputs (MIMO) are conveniently designed within reasonable footprints native to the current fabrication technologies. Chapter one presents the general layout of the various designs of the switch elements and demonstrates their novel features. This demonstration will show how waveguide disturbances in the interconnecting network from conventional switch elements can be avoided by adopting an innovative design. Some possible applications for the designed switch elements of different sizes and topologies are indicated throughout the chapter. Chapter two presents the design of the multimode interference (MMI) couplers used in the switch elements as splitters, combiners and waveguide crossovers. Simulation data and design methodologies for the multimode couplers of interest are detailed in this chapter. Chapter three presents the design and analysis of the NEMS-operated phase shifters. Both simulations and numerical analysis are utilized in the design of a 0º-180º capable NEMS-operated phase shifter. Additionally, the response of some of the designed photonic phased array switch elements is demonstrated in this chapter. An executive summary and conclusions sections are also included in the thesis.

L’objectif de ce travail de thèse est le développement en technologie intégrée standard d’une structure de ligne de transmission optimisée en termes de pertes, d’encombrement, de facteur de qualité et surtout du choix du niveau de couplage aux fréquences millimétriques. Cette structure a été nommée CS-CPW (Coupled Slow-wave CoPlanar Waveguide). Dans un premier temps, la théorie ainsi que les modèles électriques des CS-CPW sont présentés. Grâce aux modèles et aux simulations électromagnétiques, des coupleurs directionnels avec plusieurs valeurs de couplage (3 dB, 10 dB, 18 dB) ont été conçus en technologie BiCMOS 55 nm. Ils présentent tous une très bonne directivité, elle est toujours supérieure à 15 dB. Un premier prototype de coupleur a été mesuré à 150 GHz. Dans un deuxième temps, des filtres à la base des lignes couplées ont été développés à 80 GHz en utilisant des lignes CS-CPW. Les résultats des simulations présentent des résultats concurrentiels avec l’état de l’art : 11% de bande passante relative et un facteur non-chargé autour de 25. Finalement, trois projets ont démarré à la base de ces lignes. Ces projets sont actuellement utilisés dans deux travaux de thèse et un stage : un RTPS à 47 GHz, un isolateur à 75 GHz et un balun à 80 GHz. / This work focuses on high-performances CS-CPW (Coupled Slow-wave CoPlanar Waveguide) transmission lines in classical CMOS integrated technologies for the millimiter-wave frequency band. First, the theory as well as the electrical models of the CS-CPW are presented. Thanks to the models and electromagnetic simulations, directional couplers with different coupling levels (3 dB, 10 dB, 18 dB) were designed in BiCMOS 55 nm technology. They have a good directivity, always better than 15 dB. A first prototype of a coupler was measured at 150 GHz presenting good agreement with the simulations. Next, coupled-line base filters were developed at 80 GHz using the CS-CPWs. Simulation present competitive results with the state-of-art: 11% of fractional bandwidth and a unload quality factor of 25. Finally, three projects started based on the CS-CPWs. The projects are currently used in two theses and one internship: a RTPS at 47 GHz, an isolator at 75 GHz and a balun at 80 GHz.