Techn. University, Diss., 2003--Berlin.

Submitted by Maykon Nascimento (maykon.albani@hotmail.com) on 2016-05-17T20:09:39Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Tese Leandro Colombi.pdf: 1600437 bytes, checksum: d40bc605230b5d5995a431dc205d03a6 (MD5) / Approved for entry into archive by Morgana Andrade (morgana.andrade@ufes.br) on 2016-06-03T14:24:51Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Tese Leandro Colombi.pdf: 1600437 bytes, checksum: d40bc605230b5d5995a431dc205d03a6 (MD5) / Made available in DSpace on 2016-06-03T14:24:51Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Tese Leandro Colombi.pdf: 1600437 bytes, checksum: d40bc605230b5d5995a431dc205d03a6 (MD5) / CNPQ / O Problema de Grooming de Tráfego (Traffic Grooming Problem - TGP) trata da combinação eficiente de demandas de baixa velocidade em canais de alta velocidade. Com o objetivo de melhorar a utilização da capacidade da rede, o TGP é frequentemente estudado com métodos de otimização usando como função objetivo a minimização do número de transceptores eletro-´ópticos. Por´em, como o TGP pertence á classe de problemas NP-Completo, soluções ótimas com um pequeno tempo computacional são possíveis apenas para redes pequenas (por exemplo, 6 nós). Neste trabalho são propostos novos modelos de Programação Linear Inteira (Integer Linear Programming - ILP), uma heurística e uma solução híbrida para o TGP em redes translúcidas de médio porte (aproximadamente 12 n´os). Inicialmente, são propostos dois modelos ILP para o TGP, um baseado em formulação nó-enlace e outro em enlace-caminho, de forma que seus resultados foram comparados e usados como base para modelos mais complexos. No método híbrido é usada uma heurística para selecionar os caminhos ópticos (i.e., a topologia virtual) e um modelo ILP para rotear de maneira eficiente as demandas de tráfego sobre as topologias física e virtual. A aplicação desse método permitiu, primeiramente, a quantificação dos benefícios dos caminhos ópticos transparentes, em termos da redução do número de transceptores. Além disso, a diminuição do processamento eletrônico do tráfego de trânsito também foi analisada. Para redes maiores, a fase ILP no método híbrido ainda continua sendo um gargalo para as soluções ótimas, sendo assim necessárias soluções totalmente heurísticas. Este trabalho mostra que soluções eficientes podem ser encontradas usando métodos heurísticos simples e rápidos, onde não foi necessário o aumento do custo computacional para o ajuste de parâmetros complexos relacionados a heurística. Finalmente é proposta uma integração do TGP com sobrevivência. Neste trabalho são propostos modelos ILP para formulação de um método iterativo capaz de oferecer uma proteção incremental em uma rede em malha com a minimização do número de transceptores. Além disso, são estudados dois métodos para a proteção da interconexão de redes multi-anel com dois nós de interconexão, Anel Virtual e Drop&Continue. Para essa investigação os resultados numéricos incluem o grooming de tráfego para diferentes cenários como, configurações opaca vs. translúcida e crescimentos de tráfego inter-anel vs. intra-anel. / The Traffic Grooming Problem (TGP) consists in how to arrange low-bandwidth connection requests into high-capacity lightpaths efficiently. TGP solution aims at improving network capacity utilization. The minimal number optoelectronic transceivers that enable accommodating traffic demands is often used as the objec- tive function for solving TGP. However, TGP belongs to a class of NP-hard problems and optimal solutions are only possible to be found within feasible processing time for small networks (e.g., 6 nodes). This work proposes novel Integer Linear Pro- gramming (ILP) models, heuristic and a hybrid solution to TGP for medium-sized (i.e., around 12 nodes) translucent networks. Initially, ILP models using node-link and link-path paradigms are proposed and their solutions are compared. These models lay the foundations for more complex models addressing issues on network design. A hybrid method is then proposed. It makes use of a heuristic for selecting lightpaths (i.e., the virtual topology) and an ILP model to route the traffic demands over both physical and virtual topologies efficiently. The practical implications of such approach is that it allows, for the first time, the quantification of benefits of transparent lightpaths in terms of transceiver count reduction. Moreover, the miti-gation of transit traffic processing in the electronic layer is also analyzed. For large networks the ILP phase in the hybrid approach again becomes the bottleneck for optimal network design and a fully heuristic solution is necessary. This work shows that efficient solutions can be found through a simple and fast tool for network design without the need of complex parameter tuning, as comparisons with results obtained from solving the hybrid model. Finally, the integration of TGP with survivability is proposed. This work puts forward ILP models for an iterative method using two ILP models to design networks with incremental protection with minimal num- ber of transceivers in mesh networks. Dual Node Interconnected (DNI) multi-ring topologies are studied under inter-ring traffic protection using Virtual Ring (VR) and Drop and Continue (D&C) strategies. Results compare optimal solutions that take into account traffic grooming for different network scenarios including opaque vs. translucent configurations and inter vs. intra traffic growth.

Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-05-19T17:02:32Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Luciana Pedrosa Sales.pdf: 9188948 bytes, checksum: 94448189f389783d1cbd8f2751cee2d8 (MD5) / Made available in DSpace on 2016-05-19T17:02:32Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Luciana Pedrosa Sales.pdf: 9188948 bytes, checksum: 94448189f389783d1cbd8f2751cee2d8 (MD5) Previous issue date: 2004-11-30 / Nesta dissertação apresentamos um novo conceito para otimização de sistemas WDM solitônicos, chamado Gerenciamento de Colisões. Mostramos resultados de simulações com sistemas WDM solitônicos de amplificação discreta de 2 £ 40 Gb/s, operando próximo do zero de dispersão, na banda C de transmissão, sem o uso de gerenciamento de dispersão ou quaisquer outras técnicas já consagradas (como por exemplo filtros ao longo do enlace) de minimização de efeitos físicos prejudiciais ao desempenho do sistema. Após fundamentar e explorar o conceito de Gerenciamento de Colisões, propomos o uso de três técnicas. A primeira trata-se do gerenciamento de colisões incompletas que podem ocorrer no início e no final da transmissão. Para viabilizar este gerenciamento propomos uma técnica que consiste na inserção de um atraso inicial entre pulsos de canais diferentes. Essa técnica, em um sistema otimizado, para condições apropriadas (comprimento de colisão maior que duas vezes o comprimento de amplificação), pode permitir uma melhora no desempenho de sistemas WDM solitônicos, chegando a dobrar o alcance dos mesmos, pois ela elimina a colisão incompleta inicial e, em determinados casos, a final. Outras duas técnicas sugeridas exemplificam que, por meio do gerenciamento das colisões completas, podemos melhorar o desempenho de sistemas WDM solitônicos, otimizando adequadamente o espaçamento entre canais, bem como, o espaçamento entre amplificadores do mesmo. Verificamos que a otimização correta de Sistemas WDM Solitônicos, aliado ao uso adequado do espaçamento entre canais e amplificadores, pode permitir ao sistema um alcance em torno de 1000 km, para uma taxa de erro por bit (BER) de aproximadamente 10¡12, sem o uso da técnica de gerenciamento de colisão incompleta, e em torno de 1600 km, com a utilização da mesma. / In this work we propose a new concept for optimization of Solitonic WDM Systems, called Collision-Management. We show the simulation results of 2£40 Gb/sWavelength-Division Multiplexed (WDM) Solitonic Systems. We used Lumped Amplification with Erbium-doped fiber amplifier (EDFAs) and channels working near zero dispersion in the C band (1530– 1560 nm), without using Dispersion-Management or other schemes for minimizing the physical effects that degrade the optical transmission systems. After presenting the fundamental concepts of Collision-Management, we propose three techniques to implement it. The first is incomplete Collision-Management. Incomplete Collisions can occur at the beginning or/and at the end of the transmission. For this type of Management we suggest the introduction of an Initial Delay among pulses of different channels. If used in well balanced systems, this technique can increase the range of 2 £ 40 Gb/s WDM soliton transmission systems, due to the elimination of initial and final Incomplete Collisions. In some cases it can double the reach. We suggest two techniques for Complete Collision-Management, through Optimization of Channel Spacing and Optimization of Amplifier Spacing. We also show that if correctly designed, 2 £ 40 Gb/s WDM Solitonic Systems can reach about 1000 km (with BER about 10¡12), when using the Complete Collision-Management technique, and about 1600 km if we add incomplete Collision-Management technique.

Nous assistons aujourd'hui à une explosion des demandes de calcul, de stockage et de transfert de données. Dans ce contexte, le développement des ordinateurs à haute performance est crucial mais il est limité par le débit et la consommation des interconnexions électriques entre puces ou intra-puces. La photonique sur silicium propose de lever ce verrou technologique en utilisant la maturité des procédés de fabrication de microélectronique pour concevoir des interconnexions optiques à très haut débit et à faible énergie par bit. Dans ces travaux, nous nous proposons de dimensionner un lien optique intégré sur silicium pour par exemple adresser le défi technologique des interconnexions intra-puces entre un processeur et une mémoire DRAM de dernière génération. Le lien optique conçu est multiplexé en longueur d’onde et utilise des composants intégrés à faible empreinte appelés anneaux résonants pour les fonctions de modulation et de démultiplexage. Les sources laser dont seront munis ces interconnexions consomment une puissance importante : nous nous attachons à optimiser la performance des composants utilisés en termes de puissance optique. A partir d’une analyse système, nous proposons une architecture de lien et construisons un modèle pour évaluer les pénalités en puissance optique associées au transmetteur et au récepteur du lien de communication à l’aide de simulations statiques et dynamiques. Ce modèle comprend des contributions des modulateurs et des filtres du démultiplexeur considérés individuellement ainsi que des contributions liées au multiplexage en longueur d’onde à l’émission et à la réception. Des modulateurs optiques en anneau sont fabriqués en technologie PIC25G, caractérisés en statique et en dynamique puis comparés au modèle. Enfin, des démonstrateurs multiplexés en longueur d’onde sont conçus et mis en œuvre permettant de valider nos modèles prédictifs et d'en soulever de futurs perfectionnements. / The 21st century is characterized by the explosion of demand for computing power as well as data storage and transfer. In this context, the development of high-performance computers is crucial but it is limited by the bandwidth and the energy efficiency of chip-to-chip and intra-chip electrical interconnects. Silicon photonics is a promising solution that uses microelectronics manufacturing techniques to fabricate optical components dedicated to efficient and high-bit-rate optical communication links.This work aims at designing a silicon photonic intra-chip high-bandwidth interconnect based on the example of latest-generation DRAM specifications. Wavelength division multiplexing (WDM) is used with low-footprint components called optical ring resonators for modulation and filtering.Lasers sources are a non-negligible contributor to overall system power consumption. For this reason, this thesis focuses on the optimization of ring resonators in terms of optical power. We first carry out a system analysis and propose an architecture that consists of parallel WDM links. Then a system model that evaluates optical power penalties related to the transmitter and the receiver is built up using static and dynamic simulations. Individual contributions of modulators, filters as well as the impact of adjacent channels at the transmitter and receiver sides are taken into account. Optical ring modulators are fabricated in PIC25G technology and characterized through static and dynamic measurements in order to validate our model. Finally, wavelength division multiplexed prototypes are designed and demonstrations corresponding to different WDM configurations are carried out which allows for suggestions of future improvements from the comparison with our predictive model.

Les réseaux de transport optiques constituent aujourd'hui l'infrastructure de base des systèmes de communications modernes. Etant donné les investissements colossaux nécessaires au déploiement de ces réseaux, liés en particulier aux coûts des équipements (fibres optiques, cartes, transpondeurs,...), l'optimisation du routage et de l'allocation de ressources est indispensable pour maitriser les coûts d'exploitation. Dans ce contexte, ces travaux de thèse étudient un ensemble de problèmes d'allocation de ressources qui se posent lors de la planification des réseaux SDH (Synchronous Digital Hierarchy) et WDM (Wavelength Division Multiplexing), mais aussi lors de celle des réseaux multicouches basés sur une couche de transport optique. Dans un premier temps, nous étudions le problème du routage des circuits dans les réseaux SDH avec pour objectif principal de minimiser la fragmentation de la bande passante. Nous formulons ce problème comme un programme linéaire en nombres entiers intégrant un ensemble de contraintes réalistes de routage, de transmission et de brassage et utilisant des coûts de ressources granulaires. Un algorithme exact et deux heuristiques sont proposés pour résoudre ce problème. Nous abordons également le problème du reroutage des circuits SDH qui se pose aux opérateurs lorsqu'il devient indispensable de réduire la fragmentation de la bande passante. Nous montrons sur des instances réelles des problèmes étudiés que les méthodes proposées permettent des gains économiques considérables. Dans un deuxième temps, nous étudions deux problèmes de planification pour l'optimisation des réseaux WDM. Le premier problème est celui du design de la topologie logique, c'est à dire celui de la définition des circuits (chemins) optiques permettant de router un ensemble de demandes en trafic avec un coût de transpondeurs minimal. Le second problème est celui du routage et de l'affectation de longueurs d'onde: comment router les circuits optiques définis précédemment pour minimiser le nombre de longueurs d'onde utilisées tout en respectant un ensemble de contraintes technologiques? Nous formulons ces deux problèmes comme des programmes linéaires en nombres entiers et proposons des heuristiques efficaces, de type approximation successive pour le premier problème et utilisant une approche par décomposition pour le second problème. Là encore, les résultats expérimentaux montrent que les méthodes proposées permettent d'obtenir des approximations de qualité pour des instances de très grandes tailles. Enfin, nous abordons l'allocation de ressources dans les réseaux multicouches de nouvelle génération IP/MPLS sur OTN (Optical Transport Network) sur DWDM (Dense WDM). Dans ce cas, la question à laquelle la majorité des opérateurs cherchent une réponse est celle du routage des demandes en trafic de niveau 3 permettant d'optimiser l'allocation des ressources non seulement dans la couche IP/MPLS mais aussi dans les couches sous-jacentes OTN et DWDM. Pour répondre à cette question, nous proposons un nouveau modèle d'optimisation multicouche qui tient compte d'une hiérarchie de contraintes matérielles et définit un compromis entre les coûts des ressources dans les trois couches de réseau. L'ensemble des algorithmes d'optimisation proposés ont été intégrés dans l'environnement de planification et d'optimisation de réseaux NEST de la société QoS Design, utilisé par de grands opérateurs pour planifier leurs réseaux. / Optical transport networks currently constitute base infrastructures for modern day telecommunications systems. Given the huge investments required for deploying these networks, and in particular concerning equipment costs (fiber optics, cards, transponders, etc.), routing optimization and resource allocation are indispensable issues for mastering the operational expenditures (OPEX). In this context, the work conducted in this thesis handle a set of resource allocation problems which arise while planning not only optical SDH (Synchronous Digital Hierarchy) and WDM (Wavelength Division Multiplexing) networks, but also multilayer ones based on an optical transport layer. First, the circuit routing problem in SDH networks is tackled with the main objective of minimizing the bandwidth fragmentation. This problem is formulated as an Integer Linear Program (ILP) integrating a set of realistic routing, transmission and cross-connect constraints and using granular resource costs. An exact algorithm and two heuristics are proposed to solve this problem. The rerouting problem of SDH circuits, which faces operators when it becomes absolutely necessary to reduce the bandwidth fragmentation in the network, is also addressed. For real instances of the studied problems, it is shown that the proposed methods provide considerable economic gains. Second, two planning problems for WDM network optimization is tackled. The first problem is that of the logical network design, or in other words that concerned with the definition of lightpaths to route a set of traffic demands with a minimum transponder cost. The second problem is related to the routing and the wavelength assignment: how to route the previously defined lightpaths so as to minimize the total number of assigned wavelengths while respecting a set of technological constraints? These two problems are formulated as Integer Linear Programs (ILPs) and are solved using efficient heuristics, based on a successive approximation for the first problem and a decomposition approach for the second one. Here again, experimental results show that the proposed methods allow obtaining good quality approximations for large scale instances. Finally, resource allocation in new generation multilayer networks, that is IP/MPLS over OTN (Optical Transport Network) over DWDM (Dense WDM), is addressed. In this case, the question that most of the operators seek to answer is how to route layer 3 traffic demands while optimizing resource allocation, not only in the IP/MPLS layer, but also in the underlying OTN and DWDM layers. For this purpose, a new multilayer optimization model is proposed. It takes into account a hierarchy of material constraints and defines a tradeoff between the resource costs in the three network layers. The set of proposed optimization algorithms have been integrated into the network planning and optimization environment NEST of QoS Design, which is used by major operators to plan their network.

No description available.

Wavelength Division Multiplexing Passive Optical Networks (WDM PONs) offer a great solution to satisfy the increasing demand of bandwidth. In addition, it offers a higher level of data security through virtual point to point connections. A great challenge in realizing cost-effective WDM PON is the need for a transmitter at each Optical Network Unit (ONU) with a dedicated wavelength, which overloads the total cost of the system, in addition to reducing the number of available wavelengths in the system. Remodulation scheme is an ultimate solution for these problems of WDM PONs as the downstream signal itself is remodulated with upstream data which saves the need for a laser source at the ONU side. In this thesis I propose and experimentally demonstrate a novel wavelength remodulation scheme for WDM PONs that employs Differential Phase Shift Keying (DPSK) for downstream and Return to Zero DPSK (RZ-DPSK) for upstream. The use of DPSK enhanced the system with improved receiver sensitivity and RZ-DPSK improved the tolerance toward chromatic dispersion. In addition, I investigate the Backreflection (BR) penalty resulting from beat noise of BRs with upstream signal in a bidirectional WDM PON system that uses remodulation and phase modulation as a modulation format. I experimentally demonstrate the optimal conditions to operate the system and minimize the BR penalty.

Aim of this Master´s thesis is to describe and compare most common types of optical amplifiers used in today’s networks. The first section focuses on problematic of optical transmissions and phenomenon which cause degradation of transmitted signal. It is also explained in this section why there is a need to deploy optical amplifiers. Next section describes basic principles, structure and properties of individual types of optical amplifiers. Following section describes simulations which were made to compare the performance of transmission systems with each individual type of optical amplifier. The last section contains a design of optical metropolitan network with wavelength multiplex. Based on simulations from preceding part best amplifier type and optimal amplifier placement was selected. Functionality of the design was tested and simulations described in final section.

Diploma thesis deals with the construction of a moder semiconductor optical amplifier SOA. In the first chapter optical comunication and the use of optical amplifiers is described. In the next chapter some types of optical fibers, their chemical composition and properties are described in detail. The third chapter overviews optical amplifiers, their use today, describes their advantages and disadvantages and their proper use in optical comunications. The fourth chapter describes the solution of the objective, the right layout of separate blocks and connections used in measurements. Fifth chapter describes used components, describes their basic parameters and proper use in circuit. The last chapter evaluates outputs of measurements and their impact on the objective.

In this thesis, an approach for developing single-photon sources at the 1550nm wavelength will be demonstrated, based on optical trapping of luminescent upconverting nanoparticles. A single-photon source is a source that emits a single photon at a time, and hence it is a source of quantum bits that constitutes the basic building units in quantum computers and quantum communications. The approach exploits the plasmonic properties of gold films and the waveguiding characteristics of single mode optical fibers (SMFs). We start by planar nanofabrication of subwavelength nanoapertures in a thin gold film based on finite difference time domain simulations for a peak transmission at the wavelength in question. Subsequently, using ultraviolet curable epoxy adhesion material, a nanoaperture patterned on a gold film can be transferred to an SMF tip forming a nanoantenna enhanced optical fiber tweezer (NAFT). As a final step in building the optical tweezer, a test of the capability of the integrated optical fiber tweezer to trap 20 nm, and 30nm polystyrene nanospheres, as well as luminescent upconverting nanoparticles (UCNPs), has been experimentally realized with encouraging results. In addition to the optical trapping of the luminescent nanoparticles, the nano aperture antenna can improve light coupling into the low loss optical fiber guiding channel. Also, it could have a positive influence on enhancing the photon emission rate through the Purcell effect. Furthermore, we have combined NAFT with a low insertion loss wave splitter, a wavelength-division multiplexer (WDM), to allow measuring the 1550nm photon-emission statistics on a cooled superconducting nanowire single-photon detector (SNSPD) at ~ 2.4o K. Eventually, nanoantenna enhanced optical fiber tweezers can play an essential role in optical trapping towards developing single-photon sources and the emerging technology of quantum information processing, computation, and cryptography. / Graduate