Fault localization is the process of realizing the true source of a failure from a set of collected failure notifications. Isolating failure recovery within the network optical domain is necessary to resolve alarm storm problems. The introduction of the monitoring trail (m-trail) has been proven to deliver better performance by employing monitoring resources in a form of optical trails - a monitoring framework that generalizes all the previously reported counterparts. In this dissertation, the m-trail design is explored and a focus is given to the analysis on using m-trails with established lightpaths to achieve fault localization. This process saves network resources by reducing the number of the m-trails required for fault localization and therefore the number of wavelengths used in the network. A novel approach based on Geographic Midpoint Technique, an adapted version of the Chinese Postman’s Problem (CPP) solution and an adapted version of the Traveling Salesman’s Problem (TSP) solution algorithms is introduced. The desirable features of network architectures and the enabling of innovative technologies for delivering future millimeter-waveband (mm-WB) Radio-over-Fiber (RoF) systems for wireless services integrated in a Dense Wavelength Division Multiplexing (DWDM) is proposed in this dissertation. For the conceptual illustration, a DWDM RoF system with channel spacing of 12.5 GHz is considered. The mm-WB Radio Frequency (RF) signal is obtained at each Optical Network Unit (ONU) by simultaneously using optical heterodyning photo detection between two optical carriers. The generated RF modulated signal has a frequency of 12.5 GHz. This RoF system is easy, cost-effective, resistant to laser phase noise and also reduces maintenance needs, in principle. A revision of related RoF network proposals and experiments is also included. A number of models for Passive Optical Networks (PON)/ RoF-PON that combine both innovative and existing ideas along with a number of solutions for m-trail design problem of these models are proposed. The comparison between these models uses the expected survivability function which proved that these models are liable to be implemented in the new and existing PON/ RoF-PON systems. This dissertation is followed by recommendation of possible directions for future research in this area.

Las redes ópticas de paquetes se han convertido en los últimos años en uno de los temas de vanguardia en el campo de las tecnologías de comunicaciones. El procesado de cabeceras es una de las funciones más importantes que se llevan a cabo en nodos intermedios, donde un paquete debe ser encaminado a su destino correspondiente. El uso de tecnología completamente óptica para las funciones de encaminamiento y reconocimiento de cabeceras reduce el retardo de procesado respecto al procesado eléctrico, disminuyendo de ese modo la latencia en el enlace de comunicaciones. Existen diferentes métodos de procesado de datos para implementar el reconocimiento de cabeceras. El objetivo de este trabajo es la propuesta de una nueva arquitectura para el procesado de cabeceras basado en el uso de puertas lógicas completamente ópticas. Estas arquitecturas tienen como elemento clave el interferómetro Mach-Zehnder basado en el amplificador óptico de semiconductor (SOA-MZI), y utilizan el efecto no lineal de modulación cruzada de fase (XPM) en los SOAs para realizar dicha funcionalidad. La estructura SOA-MZI con XPM es una de las alternativas más atractivas debido a las numerosas ventajas que presenta, como por ejemplo los requisitos de baja energía para las señales de entrada, su diseño compacto, una elevada relación de extinción (ER), regeneración de la señal y el bajo nivel de chirp que introducen. Este trabajo se ha centrado en la implementación de la funcionalidad lógica XOR. Mediante esta función se pueden realizar diversas funcionalidades en las redes ópticas. Se proponen dos esquemas para el reconocimiento de cabeceras basados en el uso de la puerta XOR. El primer esquema utiliza puertas en cascada. El segundo esquema presenta una arquitectura muy escalable, y se basa en el uso de un bucle de realimentación implementado a la salida de la puerta. Asimismo, también se presentan algunas aplicaciones del procesado de cabeceras para el encaminamiento de paquetes basadas en el uso d / Martínez Canet, JM. (2006). Photonic logic-gates: boosting all-optical header processing in future packet-switched networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1874 / Palancia

Dizertačná práca pojednáva o vlnových a elektromagnetických javoch, ku ktorým dochádza pri zatienení eliptického Gausovského zväzku kruhovou apretúrou. Najprv boli z Huygensovho-Fresnelovho princípu odvodené dva modely Fresnelovej difrakcie. Tieto modely poskytli nástroj pre zavedenie kontrastu difrakčného obrazca ako veličiny, ktorá kvantifikuje vplyv difrakčných javov na prevádzkové parametre optického spoja. Následne, pomocou nástrojov elektromagnetickej teórie svetla, boli odvodené štyri výrazy (dva presné a dva aproximatívne) popisujúce geometrický útlm optického spoja. Zároveň boli skúmané tri rôzne prípady odsmerovania zväzku - priečne posunutie a uhlové odsmerovanie vysielača, resp. prijímača. Bol odvodený výraz, ktorý tieto prípady kvantifikuje ako útlm elipticky symetrického Gausovského zväzku. Všetky vyššie uvedené modely boli overené v laboratórnych podmienkach, aby sa vylúčil vplyv iných javov. Nakoniec práca pojednáva o návrhu plne fotonického optického terminálu. Najprv bol ukázaný návrh optického vysielača nasledovaný vývojom optomechanickej sústavy prijímača. Pomocou nástrojov geometrickej a maticovej optiky boli vypočítané parametre spoja a odhad tolerancie pri zamierení spoja.

<p>One of the longstanding goals of photonics research has been to obtain strong optical nonlinearities. A promising method to achieve this goal is to operate in the so-called epsilon near zero (ENZ) spectral regime, where the real part of the dielectric permittivity changes sign. If accompanied by low losses, this region enables a platform to achieve extraordinarily high nonlinear response, along with many other interesting optical phenomena. In this work, some of the common all-optical switching structures employing homogeneous ENZ materials are investigated under varying conditions of frequency, incidence angle, and polarization. The optimum switching conditions have been highlighted to pave the way forward to the best experimental configurations in future studies. Moreover, the properties of some of the emerging novel plasmonic materials such as aluminum-doped zinc oxide (AZO) and titanium nitride (TiN) are investigated, specifically for ENZ applications. Their thickness-dependent crystalline structure and carrier densities are employed as a method to control their optical properties. A near-perfect absorption scheme is demonstrated utilizing the Ferrell-Berreman mode occurring at the ENZ region of ultrathin AZO and TiN film. The ENZ frequency and the associated absorption peak of AZO are engineered through thickness-dependence to cover most of the telecom range. This work covers the theoretical background for ENZ nonlinearities and looks into the materials aspect for better control of nonlinearities in experimental realizations.</p>

No description available.

Ce travail de thèse rapporte la production tout optique de condensats de Bose-Einstein de 39K. Une étape clé du processus expérimental est l’obtention d’un nuage suffisamment froid permettant le chargement direct d’un piège dipolaire de manière efficace. Notre solution est l’utilisation d’une mélasse fonctionnant dans le bleu de la raie D1 de cet alcalin conduisant à une densité dans l’espace des phases élevée et ainsi au chargement direct d’un grand nombre d’atomes dans un piège à 1550 nm. Le nuage est ensuite polarisé puis comprimé dans un piège dipolaire croisé avant d’entamer un refroidissement évaporatif efficace au voisinage d’une résonance de Feshbach. Ce processus permet la production rapide de condensats de Bose-Einstein toutes les 7 secondes sur notre expérience. Ces nuages dégénérés représentent le point de départ pour la conduite d’expériences visant à étudier les effets du désordre dans les gaz quantiques en dimensions réduites. Nous envisageons l’étude du diagramme de phase du gaz de Bose bidimensionnel désordonné, de la localisation d’Anderson en dimension deux ainsi que l’étude de l’influence du désordre sur un soliton brillant dans une géométrie unidimensionnelle. / This thesis presents the all optical production of 39K Bose-Einstein condensates. A key point in the process is the sub-Doppler cooling that allows for an efficient loading of an optical dipole trap. To this aim we use a gray molasses scheme working on the blue side of the D1 line of this alkali that leads to a high phase space density and a high number of trapped atoms in a 1550 nm optical trap. The cloud is then polarized and compressed in a crossed dipole trap before starting an efficient forced evaporation close to a Feshbach resonance. This process allows us to produce Bose-Einstein condensates every 7 seconds with our experiment. Those degenerate clouds represent the starting point of experiments aiming to study the influence of disorder on quantum gases in low dimensions. We discuss the perspectives to study of the phase diagram of the two-dimensional disordered Bose gas as well as the Anderson localization phenomenon in two dimensions and the behaviour of bright solitons in a disordered potential in a one-dimensional geometry.

Le potassium 39 est l'un des alcalins pour lesquels il est possible de contrôler les interactions entre atomes grâce à l'utilisation de résonances de Feshbach. Cette thèse présente un protocole rapide et performant de production de condensats de Bose-Einstein tout optiques de 39K. Notre technique s'appuie sur l'utilisation de mélasses grises permettant de refroidir suffisamment le nuage atomique pour charger directement un piège optique, ainsi que sur une phase d'évaporation optique réalisée au voisinage d'une résonance de Feshbach afin de contrôler le taux de collisions entre atomes. Des études dans divers mélanges de spins nous ont permis d'observer de nouvelles résonances de Feshbach en onde p ainsi qu'une résonance en onde d. Cette dernière, présentant des caractéristiques peu usuelles, a été étudiée plus en détails afin de comprendre les processus de collisions en jeu. Le modèle développé, faisant intervenir deux étapes de collision à deux corps, permet d'expliquer les résultats expérimentaux obtenus. Dans les gaz de Bose dégénérés de 39K produits, le contrôle des interactions au voisinage de la résonance de Feshbach à 560,7 Gauss pour les atomes de 39K dans l'état |F=1,mF=-1> nous a permis d'adresser différents problèmes physiques. Dans le cas d'interactions répulsives, nous étudions l'expansion d'un condensat de Bose-Einstein dans le crossover dimensionel 1D-3D tandis que pour des interactions attractives, nous formons des solitons brillants dans un piège optique unidimensionnel. Les perspectives d'étude de ces gaz de Bose dégénérés auto-confinés dans des milieux désordonnés sont également discutées. / Potassium 39 is an alkali allowing to control the interactions between atoms thanks to Feshbach resonances. This thesis presents a fast and efficient way to produce all-optical Bose-Einstein condensates of 39K. Our technique is first taking advantage of gray molasses cooling leading to a cold enough sample to directly load an optical trap. Then an optical evaporation is performed near a Feshbach resonance to control the collision rate. Studies in various spin mixtures have allowed us to observe new p-wave Feshbach resonances and a d-wave Feshbach resonance. The later presents unusual properties and has been studied in details to understand the collision processes involved. The model developped is a two stage model, each one of them involving a two body collision. It explains the experimental results obtained. In the produced 39K degenerate Bose gases, tuning interactions near the Feshbach resonance at 560,7 Gauss for the atoms in |F=1,mF=-1> has allowed us to adress different physical problems. For repulsive interactions, we study the expansion of a Bose-Einstein condensate in the 1D-3D dimensional crossover. For attractive interactions we produce bright solitons in a one-dimensional optical trap. Perspectives concerning the study of those degenerate self-confined Bose gases in disordered media are also discussed.

This thesis reports an experimental characterization of the ultrafast gain and refractive index dynamics of a novel InAs/InGaAsP/InP quantum-dot (QD) semiconductor optical amplifier (SOA) operating near 1.55-µm wavelengths, assessing its high-speed performance characteristics for the first time. The thesis also studies the influence of the degree of quantum confinement on the dynamics of SOAs by comparing the zero-dimensional (0-D) QD's dynamics to those in 1-D InAs/InAlGaAs/InP quantum-dash (QDash), and 2-D InGaAsP/InGaAsP/InP quantum-well (QW) SOAs, both of which also operate near 1.55-µm wavelengths, and are made with matching or similar materials and structures. The ultrafast (around 1 ps) and long-lived (up to 2 ns) amplitude and phase dynamics of the SOAs are characterized via advanced heterodyne pump-probe measurements with 150-femtosecond resolution. It is found that the QD SOA has an 80-picosecond amplitude, and 110-picosecond phase recovery lifetime in the gain regime, 4-6 times faster than the QDash and QW recovery lifetimes, as well as reduced ultrafast transients, giving it the best properties for high-speed (> 100 Gb/s) all-optical signal processing in the important telecommunications wavelength bands. An impulse response model is developed and used to analyze the dynamics, facilitating a comparison of the gain compression factors, time-resolved linewidth enhancement factors (alpha-factors), and instantaneous dynamic coefficients (two-photon absorption and nonlinear refractive-index coefficients) amongst the three structures. The quantum-dot device is found to have the lowest effective alpha-factor, 2-10, compared to 8-16 in the QW, as well as time-resolved alpha-factors lower than in the QW—promising for reduced-phase-transient operation at high bitrates. Significant differences in the alpha-factors of lasers with the same structure are found, due to the differences between gain changes that are induced optically or through the electrical bias. The relative contributions of stimulated transitions and free-carrier absorption to the total carrier heating dynamics in SOAs of varying dimensionality are also reported for the first time. Examining the QD electroluminescence and linear gain spectra in combination with the carrier dynamics also brings about conclusions on the nature of the quantum confinement, dot energy-level structure, and density of states—aspects of the material that have not been previously well understood.

This thesis reports an experimental characterization of the ultrafast gain and refractive index dynamics of a novel InAs/InGaAsP/InP quantum-dot (QD) semiconductor optical amplifier (SOA) operating near 1.55-µm wavelengths, assessing its high-speed performance characteristics for the first time. The thesis also studies the influence of the degree of quantum confinement on the dynamics of SOAs by comparing the zero-dimensional (0-D) QD's dynamics to those in 1-D InAs/InAlGaAs/InP quantum-dash (QDash), and 2-D InGaAsP/InGaAsP/InP quantum-well (QW) SOAs, both of which also operate near 1.55-µm wavelengths, and are made with matching or similar materials and structures. The ultrafast (around 1 ps) and long-lived (up to 2 ns) amplitude and phase dynamics of the SOAs are characterized via advanced heterodyne pump-probe measurements with 150-femtosecond resolution. It is found that the QD SOA has an 80-picosecond amplitude, and 110-picosecond phase recovery lifetime in the gain regime, 4-6 times faster than the QDash and QW recovery lifetimes, as well as reduced ultrafast transients, giving it the best properties for high-speed (> 100 Gb/s) all-optical signal processing in the important telecommunications wavelength bands. An impulse response model is developed and used to analyze the dynamics, facilitating a comparison of the gain compression factors, time-resolved linewidth enhancement factors (alpha-factors), and instantaneous dynamic coefficients (two-photon absorption and nonlinear refractive-index coefficients) amongst the three structures. The quantum-dot device is found to have the lowest effective alpha-factor, 2-10, compared to 8-16 in the QW, as well as time-resolved alpha-factors lower than in the QW—promising for reduced-phase-transient operation at high bitrates. Significant differences in the alpha-factors of lasers with the same structure are found, due to the differences between gain changes that are induced optically or through the electrical bias. The relative contributions of stimulated transitions and free-carrier absorption to the total carrier heating dynamics in SOAs of varying dimensionality are also reported for the first time. Examining the QD electroluminescence and linear gain spectra in combination with the carrier dynamics also brings about conclusions on the nature of the quantum confinement, dot energy-level structure, and density of states—aspects of the material that have not been previously well understood.

This work develops an exact logical operation model to predict the performance of the all-optical shared-memory architecture (OSMA) class of packet switches and provides a means to obtain a reasonable approximation of OSMA switch performance within certain types of networks, including the Banyan family. All-optical packet switches have the potential to far exceed the bandwidth capability of their current electronic counterparts. However, all-optical switching technology is currently not mature. Consequently, all-optical switch fabrics and buffers are more constrained in size and can cost several orders of magnitude more than those of electronic switches. The use of shared-memory buffers and/or links with multiple parallel channels (channel grouping) have been suggested as ways to maximize switch performance with buffers of limited size. However, analysis of shared-memory switches is far more difficult than for other commonly used buffering strategies. Obtaining packet loss performance by simulation is often not a viable alternative to modeling if low loss rates or large networks are encountered. Published models of electronic shared-memory packet switches (ESMP) have primarily involved approximate models to allow analysis of switches with a large number of ports and/or buffer cells. Because most ESMP models become inaccurate for small switches, and OSMA switches, unlike ESMP switches, do not buffer packets unless contention occurs, existing ESMP models cannot be applied to OSMA switches. Previous models of OSMA switches were confined to isolated (non-networked), symmetric OSMA switches using channel grouping under random traffic. This work is far more general in that it also encompasses OSMA switches that (1) are subjected to bursty traffic and/or with input links that have arbitrary occupancy probability distributions, (2) are interconnected to form a network and (3) are asymmetric.