The main goal of the master’s thesis was to familiarize with optical networks dilemma and its measuring during fabrication. The whole thesis is divided into several parts where the first part deals with optic fiber dilemma. It describes its kinds, properties and also suggests a basic principle of optic signal dispersion using these fibers. It describes also optical network FTTx architecture (Fiber To The x). The second part of the thesis focuses on methods of measuring key parameters of optical networks. Is brings out the methods of measuring optical loss and dispersive influences. The last and final part in focused on creating a methodical manual for measuring these networks during its fabrication and verifying measuring methods stated in the theoretical part inside a real network. Measuring was implemented on an optical network of Masaryk University in Brno.

Thesis is divided into two parts. The first part is written rather in theoretical way. It deals with general formation of the dispersion mathematically and verbally. It focuses on the chromatic and polarization mode dispersion. Different types of optical fibers for category G.65X are mentioned as well in connection with the ITU-T. Further attention is drawn first to compensation and then the measurement both of the mentioned dispersions. The thesis describes also analyzers and their main features. The second part is devoted to practical measurements of polarization mode dispersion. In the beginning there are described the components used for construction of the optical measurements and topologies. It is followed by an analysis of an each optical link. The results of these measurement methods and their mutual comparisons are at the end of this section. Measurements in temperature chamber is the subject of a further practical part, which from the beginning captures the essential features of the temperature chamber. This is followed by a description of the measurements, analyses and final valuation depending on the amount of polarization mode dispersion versus the temperature.

Le projet FUI12 RLDO – dans le cadre duquel s’inscrit cette thèse – préconise une solution de réseau de topologie en étoile passive pour la montée en débit des réseaux domestiques. Cette solution de réseau rencontre des difficultés dans son implémentation avec la non-uniformité des puissances des ports de sortie des coupleurs multimodes. L’analyse de ce point nous a permis de comprendre que les propriétés des modes de propagation dans les éléments du réseau jouent un rôle clé dans les problèmes rencontrés. Pour caractériser la propagation dans le réseau, nous avons développé un banc de réflectométrie optique complexe dans le domaine fréquentiel. Les phénomènes limitant la sensibilité à la phase – liés en particulier à la non-linéarité du balayage en fréquence de la source laser – sont étudiés pour contribuer à une meilleure compréhension des mécanismes. Puis les performances de la mesure en intensité et en phase de l’instrument que nous avons mis en place sont testées. Nous avons aussi étudié les conditions de résolution optimales pour caractériser les modes d’un guide multimode et analysé l’incertitude sur la dispersion chromatique dans le cas où il est impossible de déterminer si on a accès à un mode ou plusieurs modes dans un diagramme de dispersion donné. Nous introduisons par la suite une méthode d’analyse temps-fréquence adaptative, permettant d’obtenir les courbes de dispersions avec une résolution optimale. Cette méthode nous a permis de montrer le caractère quasi-monomode, en condition d’excitation monomode, de la fibre multimode spéciale RLDO à 1310 nm et à 1550 nm. L’analyse de la propagation dans les fibres optiques, associée au modèle que nous avons développé pour comprendre le fonctionnement des coupleurs multimodes, a permis d’expliquer les difficultés rencontré avec les premières expérimentations de la topologie de réseau en étoile passive multimode et d’envisager des pistes de réalisation d’un prototype de réseau fonctionnel / In order to develop high capacity future-proof home network, the FUI 12 RLDO project suggests passive star network topology using multimode couplers. This topology encounters implementation difficulties due to the non-uniformity of the power distribution in the output ports of multimode couplers. Analyzing this problem shows that the properties of modes propagating in the network elements plays a key role in this non-uniform characteristics of multimode couplers. In order to characterize these modes propagating in the network, we have developed a complex optical frequency domain reflectometry (OFDR) setup. The phenomena limiting the sensitivity to the phase in OFDR – in fact, those related to the non-linear frequency tuning of the laser source - are investigated to contribute to a better understanding of the limiting mechanisms. Then we have tested the intensity and phase measurement performance of the developed setup. Later, we studied the optimal resolution conditions to characterize the modes in a multimode waveguide. We have also analyzed the uncertainty of the measurement of the chromatic dispersion of modes in case where it is impossible to determine whether one or several modes are present in a given dispersion curve. Additionally, we have introduced an adaptive time-frequency method, to obtain the dispersion curves with optimal resolution. This method allows us to show the versatility of the special RLDO multimode fiber (single-mode behavior under single-mode excitation at 1310 nm and 1550 nm). The analysis of the propagation in the optical fibers, associated with a model we have developed to study the behavior of multimode couplers, has permitted to explain encountered difficulties with the experiments of the multimode passive star network topology. This also gives insights to develop a functional prototype of network

Dans un monde de plus en plus pollué par l'activité industrielle, la détection des espèces gazeuses nocives dans l'atmosphère est d'une importance essentielle. Le marché des capteurs de gaz est déjà bien développé, avec la présence de diverses technologies et principes de détection, chacune présentant des avantages et des inconvénients intrinsèques. Dans le cadre de cette thèse, un alliage entre deux ou plusieurs technologies de détection typiquement utilisées de façon autonome a été visée, afin d'améliorer les performances globales des systèmes capteurs ainsi formées. A ce fin, nous avons conçu et étudié des dispositifs capteurs basées sur la transduction optique, couplée à un matériau sensible au gaz cible à détecter. Plus précisément, nous avons intégré pour la première fois un matériau catalyseur pouvant accélérer le taux d'oxydation des espèces chimiques (tel le monoxyde de carbone ou l'hydrogène) avec une architecture optique capable d'absorber la chaleur cédée lors de cette oxydation. L'augmentation de température occasionnée est traduite en une variation d'intensité lumineuse constituante le signal de sortie du capteur. Les travaux effectués sur les mesures de la dispersion thermique et chromatique de l'indice de réfraction des matériaux constituant le transducteur optique par des techniques d'optique guidé, ellipsométrie et des techniques photométriques sont présentés. Le sondage par moyen optique des propriétés électriques des matériaux semiconducteurs a également été étudié, y compris les variations de ces propriétés en présence des gaz oxydants, réducteurs et combustibles. / In a world suffering from increasing air pollution due to spiraling industrial activity, the detection of toxic gasses in the atmosphere is of paramount importance. The gas detector market is already well developed, and features a wide variety of detection technologies and techniques, each presenting its own set of intrinsic advantages and drawbacks. In this thesis, a combination of two or more technologies typically used independently has been studied in order to improve the global performances of gas detection systems. To this length, we have conceived and studied detector architectures based upon optical transduction systems, coupled with a material presenting a specific sensitivity to the target gas. More precisely, we have for the first time integrated a catalyst designed to accelerate the oxidation rate of chemical species (such as carbon monoxide or hydrogen) with an optical component capable of absorbing the heat generated by the oxidation reaction. The associated increase in temperature is translated to a variation of the optical intensity comprising the exit signal of the detector. The work carried out measuring the chromatic and temperature dispersion of the refractive index of the materials comprising the optical transduction component by guided mode techniques, ellipsometry and photometric techniques is presented. The optical probing of the electrical properties of semiconductor materials has also been studied, including the variations of these properties following interactions with oxidizing, reducing, or combustible gasses.

In den letzten Jahrzehnten ist das globale Kommunikationssystem in einem immer größerem Maße ein integraler Bestandteil des täglichen Lebens geworden. Optische Kommunikationssysteme sind die technologische Basis für diese Entwicklung. Nur Fasern können die riesige benötigte Bandbreite bereitstellen. Während für die ersten optischen Übertragungssysteme die Faser als "flacher" Kanal betrachtet werden konnte, machen Wellenlängenmultiplex und steigende Übertragungsraten die Einbeziehung von immer mehr physikalischen Effekten notwendig. Bei einer Erhöhung der Kanaldatenrate auf 40 Gbit/s und mehr ist die statische Kompensation von chromatischer Dispersion nicht mehr ausreichend. Die intrinsische Toleranz der Modulationsformate gegenüber Dispersion nimmt quadratisch mit der Symbolrate ab. Daher können beispielsweise durch Umwelteinflüsse hervorgerufene Dispersionsschwankungen die Dispersionstoleranz der Modulationsformate überschreiten. Dies macht eine adaptive Dispersionskompensation notwendig, was gleichzeitig auch Dispersionsmonitoring erfordert, um den adaptiven Kompensator steuern zu können. Vorhandene Links können mit Restdispersionskompensatoren ausgestattet werden, um sie für Hochgeschwindigkeitsübertragungen zu ertüchtigen. Optische Kompensationstechniken sind unabhängig von der Kanaldatenrate. Daher wird eine Erhöhung der Datenrate problemlos unterstützt. Optische Kompensatoren können WDM-fähig gebaut werden, um mehrere Kanäle auf einmal zu entzerren. Das Buch beschäftigt sich mit optischen Delay-Line-Filtern als eine Klasse von optischen Kompensatoren. Die Filtersynthese von solchen Delay-Line-Filtern wird behandelt. Der Zusammenhang zwischen optischen Filtern und digitalen FIR-Filtern mit komplexen Koeffizienten im Zusammenhang mit kohärenter Detektion wird aufgezeigt. Iterative und analytische Methoden, die die Koeffizienten für dispersions- und dispersions-slope-kompensierende Filter produzieren, werden untersucht. Genauso wichtig wie die Kompensation von Dispersion ist die Schätzung der Dispersion eines Signals. Mit Delay-Line-Filtern können die Restseitenbänder eines Signals genutzt werden, um die Dispersion zu messen. Alternativ kann nichtlineare Detektion angewandt werden, um die Pulsverbreiterung, die hauptsächlich von der Dispersion herrührt, zu schätzen. Mit gemeinsamer Dispersionskompensation und Dispersionsmonitoring können Dispersionskompensatoren auf die Signalverzerrungen eingestellt werden. Spezielle Eigenschaften der Filter zusammen mit der analytischen Beschreibung können genutzt werden, um schnelle und zuverlässige Steueralgorithmen zur Filtereinstellung bereitzustellen. Schließlich wurden Prototypen derartiger faseroptischen Kompensatoren von chromatischer Dispersion und Dispersions-Slope hergestellt und charakterisiert. Die Einheiten und ihr Systemverhalten wird gezeigt und diskutiert. / Over the course of the past decades, the global communication system has become a central part of people's everyday lives. Optical communication systems are the technological basis for this development. Only fibers can provide the huge bandwidth that is required. Where the fiber could be regarded as a flat channel for the first optical transmission systems wavelength multiplexing and increasing line rates made it necessary to take more and more physical effects into account. When the line rates are increased to 40 Gbit/s and higher static chromatic dispersion compensation is not enough. The modulation format's intrinsic tolerance for dispersion decreases quadratically with the symbol rate. Thus, environmentally induced chromatic dispersion fluctuations may exceed the dispersion tolerance of the modulation formats. This makes an adaptive dispersion compensation necessary implying also the need for a monitoring scheme to steer the adaptive compensator. Legacy links that are CD-compensated by DCFs can be upgraded with residual dispersion compensators to make them ready for high speed transmission. Optical compensation is independent from the line rate. Hence, increasing the data rates is inherently supported. Optical compensators can be built WDM ready compensating multiple channels at once. The book deals with optical delay line filters as one class of optical compensators. The filter synthesis of such delay line filters is addressed. The connection between optical filters and digital FIR filters with complex coefficients that are used in conjunction with coherent detection could be shown. Iterative and analytical methods that produce the coefficients for dispersion (and also dispersion slope) compensating filters are researched. As important as the compensation of dispersion is the estimation of the dispersion of a signal. Using delay line filters, the vestigial sidebands of a signal can be used to measure the dispersion. Alternatively, nonlinear detection can be used to estimate the pulse broadening which is caused mainly by dispersion. With dispersion compensation and dispersion monitoring, dispersion compensators can be adapted to the signal's impairment. Special properties of the filter in conjunction with an analytical description can be used to provide a fast and reliable control algorithm for setting the filter to a given dispersion and centering it on a signal. Finally, prototypes of such fiber optic chromatic dispersion and dispersion slope compensation filters were manufactured and characterized. The device and system characterization of the prototypes is presented and discussed.

This thesis focuses on 3D computer graphics and the continuous maximisation of rendering quality and performance. Its main focus is the critical analysis of numerous real-time rendering algorithms and the construction of an empirically derived system for the high-speed rendering of shader-based special effects, lighting effects, shadows, reflection and refraction, post-processing effects and the processing of physics. This critical analysis allows us to assess the relationship between rendering quality and performance. It also allows for the isolation of key algorithmic weaknesses and possible bottleneck areas. Using this performance data, gathered during the analysis of various rendering algorithms, we are able to define a selection engine to control the real-time cycling of rendering algorithms and special effects groupings based on environmental conditions. Furthermore, as a proof of concept, to balance Central Processing Unit (CPU) and Graphic Processing Unit (GPU) load for and increased speed of execution, our selection system unifies the GPU and CPU as a single computational unit for physics processing and environmental mapping. This parallel computing system enables the CPU to process cube mapping computations while the GPU can be tasked with calculations traditionally handled solely by the CPU. All analysed and benchmarked algorithms were implemented as part of a modular rendering engine. This engine offers conventional first-person perspective input control, mesh loading and support for shader model 4.0 shaders (via Microsoft’s High Level Shader Language) for effects such as high dynamic range rendering (HDR), dynamic ambient lighting, volumetric fog, specular reflections, reflective and refractive water, realistic physics, particle effects, etc. The test engine also supports the dynamic placement, movement and elimination of light sources, meshes and spatial geometry. Critical analysis was performed via scripted camera movement and object and light source additions – done not only to ensure consistent testing, but also to ease future validation and replication of results. This provided us with a scalable interactive testing environment as well as a complete solution for the rendering of computationally intensive 3D environments. As a full-fledged game engine, our rendering engine is amenable to first- and third-person shooter games, role playing games and 3D immersive environments. Evaluation criteria (identified to access the relationship between rendering quality and performance), as mentioned, allows us to effectively cycle algorithms based on empirical results and to distribute specific processing (cube mapping and physics processing) between the CPU and GPU, a unification that ensures the following: nearby effects are always of high-quality (where computational resources are available), distant effects are, under certain conditions, rendered at a lower quality and the frames per second rendering performance is always maximised. The implication of our work is clear: unifying the CPU and GPU and dynamically cycling through the most appropriate algorithms based on ever-changing environmental conditions allow for maximised rendering quality and performance and shows that it is possible to render high-quality visual effects with realism, without overburdening scarce computational resources. Immersive rendering approaches used in conjunction with AI subsystems, game networking and logic, physics processing and other special effects (such as post-processing shader effects) are immensely processor intensive and can only be successfully implemented on high-end hardware. Only by cycling and distributing algorithms based on environmental conditions and through the exploitation of algorithmic strengths can high-quality real-time special effects and highly accurate calculations become as common as texture mapping. Furthermore, in a gaming context, players often spend an inordinate amount of time fine-tuning their graphics settings to achieve the perfect balance between rendering quality and frames-per-second performance. Using this system, however, ensures that performance vs. quality is always optimised, not only for the game as a whole but also for the current scene being rendered – some scenes might, for example, require more computational power than others, resulting in noticeable slowdowns, slowdowns not experienced thanks to our system’s dynamic cycling of rendering algorithms and its proof of concept unification of the CPU and GPU. / Thesis (PhD)--University of Pretoria, 2012. / Computer Science / unrestricted

The aim of this master´s thesis is an explanation of the problem of transport optical networks with Dense Wavelength Division Multiplexing. DWDM principle, properties and limit of transmission system. Focus of thesis is also specification properties of migration transmission system to higher speed 40G, 100G and in future to 400G. Part of thesis is outlined the basic division of multiplexing system, there are discussed the basic solutions of wavelength multiplexes CWDM and DWDM, focus for the effects of nonlinear phenomena and parasitic modulation FWM, SPM and XPM in modulation DP-QPSK and 16-QAM. In practicle part we will make measurement of properties of 10G and then experimental measurement parameters on 100G.

In den letzten Jahrzehnten ist das globale Kommunikationssystem in einem immer größerem Maße ein integraler Bestandteil des täglichen Lebens geworden. Optische Kommunikationssysteme sind die technologische Basis für diese Entwicklung. Nur Fasern können die riesige benötigte Bandbreite bereitstellen. Während für die ersten optischen Übertragungssysteme die Faser als "flacher" Kanal betrachtet werden konnte, machen Wellenlängenmultiplex und steigende Übertragungsraten die Einbeziehung von immer mehr physikalischen Effekten notwendig. Bei einer Erhöhung der Kanaldatenrate auf 40 Gbit/s und mehr ist die statische Kompensation von chromatischer Dispersion nicht mehr ausreichend. Die intrinsische Toleranz der Modulationsformate gegenüber Dispersion nimmt quadratisch mit der Symbolrate ab. Daher können beispielsweise durch Umwelteinflüsse hervorgerufene Dispersionsschwankungen die Dispersionstoleranz der Modulationsformate überschreiten. Dies macht eine adaptive Dispersionskompensation notwendig, was gleichzeitig auch Dispersionsmonitoring erfordert, um den adaptiven Kompensator steuern zu können. Vorhandene Links können mit Restdispersionskompensatoren ausgestattet werden, um sie für Hochgeschwindigkeitsübertragungen zu ertüchtigen. Optische Kompensationstechniken sind unabhängig von der Kanaldatenrate. Daher wird eine Erhöhung der Datenrate problemlos unterstützt. Optische Kompensatoren können WDM-fähig gebaut werden, um mehrere Kanäle auf einmal zu entzerren. Das Buch beschäftigt sich mit optischen Delay-Line-Filtern als eine Klasse von optischen Kompensatoren. Die Filtersynthese von solchen Delay-Line-Filtern wird behandelt. Der Zusammenhang zwischen optischen Filtern und digitalen FIR-Filtern mit komplexen Koeffizienten im Zusammenhang mit kohärenter Detektion wird aufgezeigt. Iterative und analytische Methoden, die die Koeffizienten für dispersions- und dispersions-slope-kompensierende Filter produzieren, werden untersucht. Genauso wichtig wie die Kompensation von Dispersion ist die Schätzung der Dispersion eines Signals. Mit Delay-Line-Filtern können die Restseitenbänder eines Signals genutzt werden, um die Dispersion zu messen. Alternativ kann nichtlineare Detektion angewandt werden, um die Pulsverbreiterung, die hauptsächlich von der Dispersion herrührt, zu schätzen. Mit gemeinsamer Dispersionskompensation und Dispersionsmonitoring können Dispersionskompensatoren auf die Signalverzerrungen eingestellt werden. Spezielle Eigenschaften der Filter zusammen mit der analytischen Beschreibung können genutzt werden, um schnelle und zuverlässige Steueralgorithmen zur Filtereinstellung bereitzustellen. Schließlich wurden Prototypen derartiger faseroptischen Kompensatoren von chromatischer Dispersion und Dispersions-Slope hergestellt und charakterisiert. Die Einheiten und ihr Systemverhalten wird gezeigt und diskutiert. / Over the course of the past decades, the global communication system has become a central part of people's everyday lives. Optical communication systems are the technological basis for this development. Only fibers can provide the huge bandwidth that is required. Where the fiber could be regarded as a flat channel for the first optical transmission systems wavelength multiplexing and increasing line rates made it necessary to take more and more physical effects into account. When the line rates are increased to 40 Gbit/s and higher static chromatic dispersion compensation is not enough. The modulation format's intrinsic tolerance for dispersion decreases quadratically with the symbol rate. Thus, environmentally induced chromatic dispersion fluctuations may exceed the dispersion tolerance of the modulation formats. This makes an adaptive dispersion compensation necessary implying also the need for a monitoring scheme to steer the adaptive compensator. Legacy links that are CD-compensated by DCFs can be upgraded with residual dispersion compensators to make them ready for high speed transmission. Optical compensation is independent from the line rate. Hence, increasing the data rates is inherently supported. Optical compensators can be built WDM ready compensating multiple channels at once. The book deals with optical delay line filters as one class of optical compensators. The filter synthesis of such delay line filters is addressed. The connection between optical filters and digital FIR filters with complex coefficients that are used in conjunction with coherent detection could be shown. Iterative and analytical methods that produce the coefficients for dispersion (and also dispersion slope) compensating filters are researched. As important as the compensation of dispersion is the estimation of the dispersion of a signal. Using delay line filters, the vestigial sidebands of a signal can be used to measure the dispersion. Alternatively, nonlinear detection can be used to estimate the pulse broadening which is caused mainly by dispersion. With dispersion compensation and dispersion monitoring, dispersion compensators can be adapted to the signal's impairment. Special properties of the filter in conjunction with an analytical description can be used to provide a fast and reliable control algorithm for setting the filter to a given dispersion and centering it on a signal. Finally, prototypes of such fiber optic chromatic dispersion and dispersion slope compensation filters were manufactured and characterized. The device and system characterization of the prototypes is presented and discussed.

[EN] The processing of radiofrequency signals using photonics means is a discipline that appeared almost at the same time as the laser and the optical fibre. Photonics offers the capability of managing broadband radiofrequency (RF) signals thanks to its low transmission attenuation, a variety of linear and non-linear phenomena and, recently, the potential to implement integrated photonic subsystems. These features open the door for the implementation of multiple functionalities including optical transportation, up and down frequency conversion, optical RF filtering, signal multiplexing, de-multiplexing, routing and switching, optical sampling, tone generation, delay control, beamforming and photonic generation of digital modulations, and even a combination of several of these functionalities. This thesis is focused on the application of vector processing in the optical domain to radiofrequency signals in two fields of application: optical beamforming, and photonic vector modulation and demodulation of digital quadrature amplitude modulations. The photonic vector control enables to adjust the amplitude and phase of the radiofrequency signals in the optical domain, which is the fundamental processing that is required in different applications such as beamforming networks for direct radiating array (DRA) antennas and multilevel quadrature modulation. The work described in this thesis include different techniques for implementing a photonic version of beamforming networks for direct radiating arrays (DRA) known as optical beamforming networks (OBFN), with the objectives of providing a precise control in terrestrial applications of broadband signals at very high frequencies above 40 GHz in communication antennas, optimizing the size and mass when compared with the electrical counterparts in space application, and presenting new photonic-based OBFN functionalities. Thus, two families of OBFNs are studied: fibre-based true time delay architectures and integrated networks. The first allow the control of broadband signals using dispersive optical fibres with wavelength division multiplexing techniques and advanced functionalities such as direction of arrival estimation in receiving architectures. In the second, passive OBFNs based on monolithically-integrated Optical Butler Matrices are studied, including an ultra-compact solution using optical heterodyne techniques in silicon-on-insulator (SOI) material, and an alternative implementing a homodyne counterpart in germanium doped silica material. In this thesis, the application of photonic vector processing to the generation of quadrature digital modulations has also been investigated. Multilevel modulations are based on encoding digital information in discrete states of phase and amplitude of an electrical signal to enhance spectral efficiency, as for instance, in quadrature modulation. The signal process required for generating and demodulating this kind of signals involves vector processing (phase and amplitude control) and frequency conversion. Unlike the common electronic or digital implementation, in this thesis, different photonic based signal processing techniques are studied to produce digital modulation (photonic vector modulation, PVM) and demodulation (PVdM). These techniques are of particular interest in the case of broadband signals where the data rate required to be managed is in the order of gigabit per second, for applications like wireless backhauling of metro optical networks (known as fibre-to-the-air). The techniques described use optical dispersion in optical fibres, wavelength division multiplexing and photonic up/down conversion. Additionally, an optical heterodyne solution implemented monolithically in a photonic integrated circuit (PIC) is also described. / [ES] El procesamiento de señales de radiofrecuencia (RF) utilizando medios fotónicos es una disciplina que apareció casi al mismo tiempo que el láser y la fibra óptica. La fotónica ofrece la capacidad de manipular señales de radiofrecuencia de banda ancha, una baja atenuación, procesados basados en una amplia variedad de fenómenos lineales y no lineales y, recientemente, el potencial para implementar subsistemas fotónicos integrados. Estas características ofrecen un gran potencial para la implementación de múltiples funcionalidades incluyendo transporte óptico, conversión de frecuencia, filtrado óptico de RF, multiplexación y demultiplexación de señales, encaminamiento y conmutación, muestreo óptico, generación de tonos, líneas de retardo, conformación de haz en agrupaciones de antenas o generación fotónica de modulaciones digitales, e incluso una combinación de varias de estas funcionalidades. Esta tesis se centra en la aplicación del procesamiento vectorial en el dominio óptico de señales de radiofrecuencia en dos campos de aplicación: la conformación óptica de haces y la modulación y demodulación vectorial fotónica de señales digitales en cuadratura. El control fotónico vectorial permite manipular la amplitud y fase de las señales de radiofrecuencia en el dominio óptico, que es el procesamiento fundamental que se requiere en diferentes aplicaciones tales como las redes de conformación de haces para agrupaciones de antenas y en la modulación en cuadratura. El trabajo descrito en esta tesis incluye diferentes técnicas para implementar una versión fotónica de las redes de conformación de haces de en agrupaciones de antenas, conocidas como redes ópticas de conformación de haces (OBFN). Se estudian dos familias de redes: arquitecturas de retardo en fibra óptica y arquitecturas integradas. Las primeras permiten el control de señales de banda ancha utilizando fibras ópticas dispersivas con técnicas de multiplexado por división de longitud de onda y funcionalidades avanzadas tales como la estimación del ángulo de llegada de la señal en la antena receptora. En la segunda, se estudian redes de conformación pasivas basadas en Matrices de Butler ópticas integradas, incluyendo una solución ultra-compacta utilizando técnicas ópticas heterodinas en silicio sobre aislante (SOI), y una alternativa homodina en sílice dopado con germanio. En esta tesis, también se han investigado técnicas de procesado vectorial fotónico para la generación de modulaciones digitales en cuadratura. Las modulaciones multinivel codifican la información digital en estados discretos de fase y amplitud de una señal eléctrica para aumentar su eficiencia espectral, como por ejemplo la modulación en cuadratura. El procesado necesario para generar y demodular este tipo de señales implica el procesamiento vectorial (control de amplitud y fase) y la conversión de frecuencia. A diferencia de la implementación electrónica o digital convencional, en esta tesis se estudian diferentes técnicas de procesado fotónico tanto para la generación de modulaciones digitales (modulación vectorial fotónica, PVM) como para su demodulación (PVdM). Esto es de particular interés en el caso de señales de banda ancha, donde la velocidad de datos requerida es del orden de gigabits por segundo, para aplicaciones como backhaul inalámbrico de redes ópticas metropolitanas (conocida como fibra hasta el aire). Las técnicas descritas se basan en explotar la dispersión cromática de la fibra óptica, la multiplexación por división de longitud de onda y la conversión en frecuencia. Además, se presenta una solución heterodina implementada monolíticamente en un circuito integrado fotónico (PIC). / [CA] El processament de senyals de radiofreqüència (RF) utilitzant mitjans fotònics és una disciplina que va aparèixer gairebé al mateix temps que el làser i la fibra òptica. La fotònica ofereix la capacitat de manipular senyals de radiofreqüència de banda ampla, una baixa atenuació, processats basats en una àmplia varietat de fenòmens lineals i no lineals i, recentment, el potencial per implementar subsistemes fotònics integrats. Aquestes característiques ofereixen un gran potencial per a la implementació de múltiples funcionalitats incloent transport òptic, conversió de freqüència, filtrat òptic de RF, multiplexació i demultiplexació de senyals, encaminament i commutació, mostreig òptic, generació de tons, línies de retard, conformació de feix en agrupacions d'antenes i la generació fotònica de modulacions digitals, i fins i tot una combinació de diverses d'aquestes funcionalitats. Aquesta tesi es centra en l'aplicació del processament vectorial en el domini òptic de senyals de radiofreqüència en dos camps d'aplicació: la conformació òptica de feixos i la modulació i demodulació vectorial fotònica de senyals digitals en quadratura. El control fotònic vectorial permet manipular l'amplitud i la fase dels senyals de radiofreqüència en el domini òptic, que és el processament fonamental que es requereix en diferents aplicacions com ara les xarxes de conformació de feixos per agrupacions d'antenes i en modulació multinivell. El treball descrit en aquesta tesi inclou diferents tècniques per implementar una versió fotònica de les xarxes de conformació de feixos en agrupacions d'antenes, conegudes com a xarxes òptiques de conformació de feixos (OBFN), amb els objectius de proporcionar un control precís en aplicacions terrestres de senyals de banda ampla a freqüències molt altes per sobre de 40 GHz en antenes de comunicacions, optimitzant la mida i el pes quan es compara amb els homòlegs elèctrics en aplicacions espacials, i la presentació de noves funcionalitats fotòniques per agrupacions d'antenes. Per tant, s'estudien dues famílies de OBFNs: arquitectures de retard en fibra òptica i arquitectures integrades. Les primeres permeten el control de senyals de banda ampla utilitzant fibres òptiques dispersives amb tècniques de multiplexació per divisió en longitud d'ona i funcionalitats avançades com ara l'estimació de l'angle d'arribada del senyal a l'antena receptora. A la segona, s'estudien xarxes de conformació passives basades en Matrius de Butler òptiques en fotònica integrada, incloent una solució ultra-compacta utilitzant tècniques òptiques heterodinas en silici sobre aïllant (SOI), i una alternativa homodina en sílice dopat amb germani. D'altra banda, també s'ha investigat en aquesta tesi tècniques de processament vectorial fotònic per a la generació de modulacions digitals en quadratura. Les modulacions multinivell codifiquen la informació digital en estats discrets de fase i amplitud d'un senyal elèctric per augmentar la seva eficiència espectral, com ara la modulació en quadratura. El processat necessari per generar i desmodular aquest tipus de senyals implica el processament vectorial (control d'amplitud i fase) i la conversió de freqüència. A diferència de la implementació electrònica o digital convencional, en aquesta tesi s'estudien diferents tècniques de processament fotònic tant per a la generació de modulacions digitals (modulació vectorial fotònica, PVM) com per la seva demodulació (PVdM). Això és de particular interès en el cas de senyals de banda ampla, on la velocitat de dades requerida és de l'ordre de gigabits per segon, per a aplicacions com backhaul sense fils de xarxes òptiques metropolitanes (coneguda com fibra fins l'aire). Les tècniques descrites es basen en explotar la dispersió cromàtica de la fibra òptica, la multiplexació per divisió en longitud d'ona i la conversió en freqüència. A més, es prese / Piqueras Ruipérez, MÁ. (2016). Photonic Vector Processing Techniques for Radiofrequency Signals [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63264

Broadband spectral content is required to support ultrashort pulses. However this broadband content is subject to dispersion and hence the pulse duration of corresponding ultrashort pulses may be stretched accordingly. I used a commercially-available adaptive ultrashort pulse shaper featuring multiphoton intrapulse interference phase scan technology to characterise and compensate for the dispersion of the optical system in situ and conducted experimental and theoretical studies in various inter-linked topics relating to the light-matter interaction. Firstly, I examined the role of broadband ultrashort pulses in novel light-matter interacting systems involving optically co-trapped particle systems in which inter-particle light scattering occurs between optically-bound particles. Secondly, I delivered dispersion-compensated broadband ultrashort pulses in a dispersive microscope system to investigate the role of pulse duration in a biological light-matter interaction involving laser-induced cell membrane permeabilisation through linear and nonlinear optical absorption. Finally, I examined some of the propagation characteristics of broadband ultrashort pulse propagation using a computer-controlled spatial light modulator. The propagation characteristics of ultrashort pulses is of paramount importance for defining the light-matter interaction in systems. The ability to control ultrashort pulse propagation by using adaptive dispersion compensation enables chirp-free ultrashort pulses to be used in experiments requiring the shortest possible pulses for a specified spectral bandwidth. Ultrashort pulsed beams may be configured to provide high peak intensities over long propagation lengths, for example, using novel beam shapes such as Bessel-type beams, which has applications in biological light-matter interactions including phototransfection based on laser-induced cell membrane permeabilisation. The need for precise positioning of the beam focus on the cell membrane becomes less strenuous by virtue of the spatial properties of the Bessel beam. Dispersion compensation can be used to control the temporal properties of ultrashort pulses thus permitting, for example, a high peak intensity to be maintained along the length of a Bessel beam, thereby reducing the pulse energy required to permeabilise the cell membrane and potentially reduce damage therein.