O presente trabalho descreve o desenvolvimento e implementação de duas configurações distintas de um receptor optoeletrônico integrado. A primeira configuração é similar a um projeto encontrado na literatura mas apresenta diversas modificações que lhe conferiram melhor desempenho em comparação ao projeto original. A segunda configuração é uma nova proposta deste trabalho. O receptor foi desenvolvido e implementado visando sua aplicação em redes de comunicações ópticas passivas (PONs) de alta velocidade comutadas a pacote, para possibilitar a utilização da técnica de multiplexação em comprimento de onda (WDM), aumentando assim a capacidade de transmissão da rede, em particular no ramo de ligação da rede de serviços com o usuário final, denominado rede de acesso. O principal objetivo do receptor aqui desenvolvido foi proporcionar uma sintonia rápida entre os canais disponíveis na rede, possibilitando sua seleção num tempo inferior àquele necessário para a transmissão de um único pacote de informação, diminuindo assim o atraso de sintonia e, por conseguinte, a perda de informação. Para tanto, os circuitos integrados implementados e caracterizados referem-se aos circuitos de chaveamento eletrônico e do amplificador de transimpedância das duas configurações investigadas. Os dados experimentais obtidos para as duas configurações confirmaram a previsão de chaveamento dos canais de entrada num intervalo de tempo da ordem de alguns nanosegundos, o que é totalmente compatível com a velocidade de transmissão das aplicações a que se destina este receptor (aproximadamente 5 Gbits/s). Adicionalmente, são apresentados os dados experimentais relativos à freqüência de corte, ganho direto, isolação, relação on/off e características de ruído dos circuitos implementados. / The present work describes the design and implementation of two configurations of an integrated optoelectronic receiver. The first one is similar to a previously reported design but with some modifications to improve its performance. The second one is a new proposal of this work. The goal of the receiver design and implementation was its application in high bit rate packet-switched passive optical networks (PONs) employing the wavelength division multiplexing (WDM) technique to increase the network capacity, in particular on the connection branch of the network core with the final user, the access network. The main goal of the receiver design was to achieve a fast channel tuning, allowing a tuning time smaller than the required for the transmission of a single information packet, decreasing the tuning latency and, therefore, the rate of information packet loss. In order to accomplish this goal, the implemented and tested integrated circuits include the electronic switching circuit and the transimpedance amplifier for both configurations investigated. The measured data for both configurations confirm the expected input channel switching time results, of about a few nanoseconds, which is certainly useful for the expected bit rate of operation (approximate 5 Gbps). Additionally, experimental results concerning cutoff frequency and bandwidth, direct gain, isolation, on/off ratio, and noise characteristics of both implemented circuits are presented.

Photonics and Optical techniques have advanced recently by a great extend to play an important role in Microwave and Radar applications. Antenna array of modern active phased array radars consist of multiple low power transmit and receive mod- ules. This demands distribution of the various Local Oscillator(LO) signals for up conversion of transmit signals and down conversion of receive signals during various modes of operation of a radar system. Additionally, these receivers require control and clock signals which are digital and low frequency analog, for the synchronization between receive modules. This is normally achieved through RF cables with complex distribution networks which add significantly higher additional weight to the arrays. During radar operations, radio frequency (RF) transmit signal needs to be distributed through the same modules which will in turn get distributed to all antenna elements of the array using RF cables. This makes the system bulky and these large number of cables are prone to Electromagnetic Interference (EMI) and need additional shielding. Therefore it is very desirable to distribute a combination of these RF, analog and digital signals using a distribution network that is less complex, light in weight and immune to EMI. Advancements in Optical and Microwave photonics area have enabled carrying of higher datarate signals on a single fiber due to its higher bandwidth capability including RF signals. This is achieved by employing Wavelength Division Multi- plexing (WDM) that combine high speed channels at different wavelengths. This work proposes, characterizes and evaluates an optical Wavelength Division Multiplexed(WDM) distribution network that will overcome the above mentioned problems in a phased array radar application. The work carries out a feasibility analysis supported with experimental measurements of various physical parameters like am- plitude, delay, frequency and phase variation for various radar waveforms over WDM links. Different configurations of optical distribution network are analyzed for multipoint distribution of both digital and RF signals. These network configurations are modeled and evaluated against various parameters that include power level, loss, cost and component count. A configuration which optimizes these parameters based on the application requirements is investigated. Considerable attention is paid to choose a configuration which does not provide excess loss, which is economically viable, compact and can be realized with minimum component count. After analysing the link configuration, multiplexing density of the WDM link is considered. In this work, since the number of signals to be distributed in radar systems are small, a coarse WDM(CWDM) scheme is considered for evaluation. A comparative study is also performed between coarse and dense WDM (DWDM) links for selection of a suitable multiplexing scheme. These configurations are modeled and evaluated with power budgeting. Even though CWDM scheme does not permit the utilisation of the available bandwidth to the fullest extent, these links have the advantage of having less hardware complexity and easiness of implementation. As the application requires signal distribution to thousands of transmit-receive modules, amplifiers are necessary to compensate for the reduction of signal level due to the high splitting ratio. Introduction of commonly available optical amplifiers like Erbium Doped Fiber Amplifier (EDFA), affect the CWDM channel output powers adversely due to their non-flat gain spectrum. Unlike DWDM systems, the channel separation of CWDM systems are much larger causing significantly high channel gain differences at the EDFA output. So an analysis is carried out for the selection of a suitable wavelength for CWDM channels to minimize the EDFA output power variation. If the gain difference is still significant, separate techniques needs to be implemented to flatten the output power at the antenna end. A CWDM configuration using C-band and L-band EDFAs is proposed and is supported with a feasibility analysis. As a part of evaluation of these links for radar applications, a mathematical model of the WDM link is developed by considering both the RF and digital sig- nals. A generic CWDM system consisting of transmitters, receivers, amplifiers, multiplexers/ demultiplexers and detectors are considered for the modeling. For RF signal transmission, the transmitters with external modulators are considered. Mod- eling is done based on a bottom-top approach where individual component models are initially modeled as a function of input current/power and later cascaded to obtain the link model. These models are then extended to obtain the wavelength dependent model ( spectral response) of the hybrid signal distribution link Further mathematical analysis of the developed link model revealed its variable separable nature in terms of the input power and wavelength. This led to significant reduction in the link equation complexity and development of some approximation techniques to easily represent the link behavior. The reduced form of the link spectral model was very essential as the initially developed wavelength model had a lot of parametric dependency on the component models. This mathematical reduction process led to simplification of the spectral model into a product of two independent functions, the input current and wavelength. It is also noticed that the total link power within specific wavelength range can be obtained by the integrating these functions over a specific link input power. After the mathematical modelling, an experimental prototype physical link is set up and characterized using various radar signals like continuous wave (CW) RF, pulsed RF, non linear frequency modulated signal (NLFM) etc. Additionally a proof of concept Radio-Over-Fiber (RoF) link is established to prove the superior transmission of microwave signal through an optical link. The analysis is supported with measurements on amplitude, delay, frequency and phase variations. The NLFM waveforms transmissions are further analysed using a matched _ltering process to confirm the side lobe requirement. Further a prototype WDM link is built to study the performance when digitally modulated channels are also multiplexed into the link. The link is again validated for signal levels, delay, frequency and phase parameters. Since amplitude and delay are deterministic, it is proposed that these parameter variations can be compensated by using suitable components either in the electrical or the optical domain. Radar systems use low frequency digital signals of different duty-cycles for synchronization and control across various transmit-receive modules. In the proposed link, these digital signals also modulate a WDM channel and hence the link is called a hybrid system. As the proposed link has EDFA to compensate for the splitting losses, there are chances of transient effects at the EDFA output for these low bitrate channels. Owing to the long carrier lifetime, low bitrate digital channels are prone to EDFA transient effects under specific signal and pump power conditions. Additionally, the synchronization signals used in radar application vary the duty-cycle over time, which is found to introduce variations in transient output. This practical challenge is further studied and the thesis for the first time, includes an analysis of EDFA transient e_ects for variable duty-cycle pulsed signals. The analysis is carried out for various parameters like bitrate, input power, pump power and duty-cycle. Investigations on EDFA transients on variable duty-cycle signals help in proposing a viable method to predict the lower duty-cycle transients from higher duty-cycle transients. The predicted transients were again validated against simulated transients and experimental results. As these transient effects are not desirable for radar signals, we propose a novel transient suppression techniques in optical and electrical domain which are validated with simulation and experimental measures. One suppression technique tries to avoid transient effect by keeping the optical input to EDFA always constant by feeding an inverted version of the original pulse into the EDFA along with the actual pulse. It is observed that as the wavelength of the inverted pulse is closer to the original input pulse, the transient effect settles faster. These EDFA transients are evaluated with WDM link configurations, where both high and low bitrate signals are co-propagated. Another challenging aspect of the link operation is the non-at gain spectrum of EDFA. i.e., EDFA provides unequal power level for various signals at WDM link output. This is especially true in the case of local oscillator signals, where it is preferable to have the same amplitude signals before feeding it to the mixer stages. But in the radar applications, this will require additional hardware circuits to equalize the signal level within a phased array antenna. This work also proposes some of the power equalization methods that can be used along with the WDM links. This part of the work is also supported with simulation model and experimental results. The analytical and experimental study of this thesis aids the evaluation process of a suitable optical Wavelength Division Multiplexed(WDM) distribution network that can be used for the distribution of both RF and digital signals. The optical WDM links being superior with its light weight, less loss and EMI/ EMC immunity provides a better solution to future class of radars.

O presente trabalho descreve o desenvolvimento e implementação de duas configurações distintas de um receptor optoeletrônico integrado. A primeira configuração é similar a um projeto encontrado na literatura mas apresenta diversas modificações que lhe conferiram melhor desempenho em comparação ao projeto original. A segunda configuração é uma nova proposta deste trabalho. O receptor foi desenvolvido e implementado visando sua aplicação em redes de comunicações ópticas passivas (PONs) de alta velocidade comutadas a pacote, para possibilitar a utilização da técnica de multiplexação em comprimento de onda (WDM), aumentando assim a capacidade de transmissão da rede, em particular no ramo de ligação da rede de serviços com o usuário final, denominado rede de acesso. O principal objetivo do receptor aqui desenvolvido foi proporcionar uma sintonia rápida entre os canais disponíveis na rede, possibilitando sua seleção num tempo inferior àquele necessário para a transmissão de um único pacote de informação, diminuindo assim o atraso de sintonia e, por conseguinte, a perda de informação. Para tanto, os circuitos integrados implementados e caracterizados referem-se aos circuitos de chaveamento eletrônico e do amplificador de transimpedância das duas configurações investigadas. Os dados experimentais obtidos para as duas configurações confirmaram a previsão de chaveamento dos canais de entrada num intervalo de tempo da ordem de alguns nanosegundos, o que é totalmente compatível com a velocidade de transmissão das aplicações a que se destina este receptor (aproximadamente 5 Gbits/s). Adicionalmente, são apresentados os dados experimentais relativos à freqüência de corte, ganho direto, isolação, relação on/off e características de ruído dos circuitos implementados. / The present work describes the design and implementation of two configurations of an integrated optoelectronic receiver. The first one is similar to a previously reported design but with some modifications to improve its performance. The second one is a new proposal of this work. The goal of the receiver design and implementation was its application in high bit rate packet-switched passive optical networks (PONs) employing the wavelength division multiplexing (WDM) technique to increase the network capacity, in particular on the connection branch of the network core with the final user, the access network. The main goal of the receiver design was to achieve a fast channel tuning, allowing a tuning time smaller than the required for the transmission of a single information packet, decreasing the tuning latency and, therefore, the rate of information packet loss. In order to accomplish this goal, the implemented and tested integrated circuits include the electronic switching circuit and the transimpedance amplifier for both configurations investigated. The measured data for both configurations confirm the expected input channel switching time results, of about a few nanoseconds, which is certainly useful for the expected bit rate of operation (approximate 5 Gbps). Additionally, experimental results concerning cutoff frequency and bandwidth, direct gain, isolation, on/off ratio, and noise characteristics of both implemented circuits are presented.

Les réseaux optiques dynamiques et flexibles font partie des scénarios d'évolution des réseaux de transport optique. Ceux-ci formeront la base de la nouvelle génération des réseaux optiques de demain et permettront le déploiement efficace des services tel que le Cloud Computing. Cette évolution est destinée à apporter flexibilité et automatisation à la couche optique, mais s'accompagne d'une complexité supplémentaire, notamment au niveau de la gestion et de la commande de cette toute nouvelle génération de réseau. Jusqu'à récemment, les protocoles de routage et de signalisation normalisés ont pris en compte plusieurs paramètres physiques tels que l'information spectrale de la bande passante, le format de modulation, et la régénération optique. Cependant, d'autres paramètres sont encore nécessaires (par exemple, les puissances optiques des liens, le gain des amplificateurs) afin de faire fonctionner efficacement de grands réseaux. Dans ce contexte, il y a un besoin d'étudier les réseaux optiques existants ainsi que les différentes méthodes de prise en compte de la couche photonique dans le plan de contrôle. Le but est d'avoir un réseau optique automatique, flexible et programmable, mais surtout efficace de point de vue économique et opérationnel. L'utilisation de la technologie à grille flexible a un impact sur les réseaux optiques existants, où presque tous les équipements devront être remplacés, ce qui entraînera un coût additionnel pour les opérateurs. Dans ce travail, nous étudions les réseaux optiques actuels et évaluons l'impact de la flexibilité sur les infrastructures existantes. Ensuite, nous identifions plusieurs paramètres optiques à contrôler et proposons des extensions protocolaires afin d'intégrer ces paramètres dans un plan de contrôle GMPLS. De plus, nous développons les algorithmes de routage et de signalisation qui permettent la mise en œuvre d'un plan de contrôle efficace qui répond au besoin de la flexibilité. Enfin, l'ensemble de nos propositions et de nos solutions sont évaluées sur plusieurs topologies réseaux avec des modèles de trafic différents dans le but de valider leur pertinence. / Dynamic and flexible optical networks are among the evolution scenarios of the optical transport networks. These form the basis of the new generation of optical networks of tomorrow and enable the effective deployment of services such as cloud computing. This evolution is intended to provide flexibility and automation to the optical layer. However, it results in additional complexity, particularly in terms of the management and control of this new network generation. Until recently, the standardized routing and signaling protocols have been taking into account several optical parameters like the spectral bandwidth information, modulation format, and optical regeneration. However, other parameters (e.g., link optical powers, gain of optical amplifiers) are still required in order to efficiently operate large optical networks. In this context, there is a need to study the existing optical networks and the different integration methods of the photonic layer in a control plane. The goal is to get an automatic optical network that is flexible, programmable, and at the same time efficient from an economical and operational perspective. The use of flexible grid technology has an impact on existing optical networks, where almost all the equipment must be replaced, resulting in an additional cost to network operators. In this work, we study the current optical networks and evaluate the impact of flexibility on the existing infrastructures. Then, we identify several physical parameters to be controlled and propose protocol extensions in order to integrate these parameters in the GMPLS control plane. In addition, we develop the routing and signaling algorithms that allow the implementation of an efficient control plane that addresses the need for flexibility. Finally, the set of our proposals and solutions are evaluated on multiple network topologies with different traffic patterns in order to validate their relevance.

Konventionelle, optische Transportnetze haben die Bereitstellung von High-Speed-Konnektivität in Form von langfristig installierten Verbindungen konstanter Bitrate ermöglicht. Die Einrichtungszeiten solcher Verbindungen liegen in der Größenordnung von Wochen, da in den meisten Fällen manuelle Eingriffe erforderlich sind. Nach der Installation bleiben die Verbindungen für Monate oder Jahre aktiv. Das Aufkommen von Grid Computing und Cloud-basierten Diensten bringt neue Anforderungen mit sich, die von heutigen optischen Transportnetzen nicht mehr erfüllt werden können. Dies begründet die Notwendigkeit einer Umstellung auf dynamische, optische Netze, welche die kurzfristige Bereitstellung von Bandbreite auf Nachfrage (Bandwidth on Demand - BoD) ermöglichen. Diese Netze müssen Verbindungen mit unterschiedlichen Bitratenanforderungen, mit zufälligen Ankunfts- und Haltezeiten und stringenten Einrichtungszeiten realisieren können. Grid Computing und Cloud-basierte Dienste führen in manchen Fällen zu Verbindungsanforderungen mit Haltezeiten im Bereich von Sekunden, wobei die Einrichtungszeiten im Extremfall in der Größenordnung von Millisekunden liegen können. Bei optischen Netzen für BoD muss der Verbindungsaufbau und -abbau, sowie das Netzmanagement ohne manuelle Eingriffe vonstattengehen. Die dafür notwendigen Technologien sind Flex-Grid-Wellenlängenmultiplexing, rekonfigurierbare optische Add / Drop-Multiplexer (ROADMs) und bandbreitenvariable, abstimmbare Transponder. Weiterhin sind Online-Ressourcenzuweisungsmechanismen erforderlich, um für jede eintreffende Verbindungsanforderung abhängig vom aktuellen Netzzustand entscheiden zu können, ob diese akzeptiert werden kann und welche Netzressourcen hierfür reserviert werden. Dies bedeutet, dass die Ressourcenzuteilung als Online-Optimierungsproblem behandelt werden muss. Die Entscheidungen sollen so getroffen werden, dass auf lange Sicht ein vorgegebenes Optimierungsziel erreicht wird. Die Ressourcenzuweisung bei dynamischen optischen Netzen lässt sich in die Teilfunktionen Routing- und Spektrumszuteilung (RSA), Verbindungsannahmekontrolle (CAC) und Dienstgütesteuerung (GoS Control) untergliedern. In dieser Dissertation wird das Problem der Online-Ressourcenzuteilung in dynamischen optischen Netzen behandelt. Es wird die Theorie der Markov-Entscheidungsprozesse (MDP) angewendet, um die Ressourcenzuweisung als Online-Optimierungsproblem zu formulieren. Die MDP-basierte Formulierung hat zwei Vorteile. Zum einen lassen sich verschiedene Optimierungszielfunktionen realisieren (z.B. die Minimierung der Blockierungswahrscheinlichkeiten oder die Maximierung der wirtschaftlichen Erlöse). Zum anderen lässt sich die Dienstgüte von Gruppen von Verbindungen mit spezifischen Verkehrsparametern gezielt beeinflussen (und damit eine gewisse GoS-Steuerung realisieren). Um das Optimierungsproblem zu lösen, wird in der Dissertation ein schnelles, adaptives und zustandsabhängiges Verfahren vorgestellt, dass im realen Netzbetrieb rekursiv ausgeführt wird und die Teilfunktionen RSA und CAC umfasst. Damit ist das Netz in der Lage, für jede eintreffende Verbindungsanforderung eine optimale Ressourcenzuweisung zu bestimmen. Weiterhin wird in der Dissertation die Implementierung des Verfahrens unter Verwendung eines 3-Way-Handshake-Protokolls für den Verbindungsaufbau betrachtet und ein analytisches Modell vorgestellt, um die Verbindungsaufbauzeit abzuschätzen. Die Arbeit wird abgerundet durch eine Bewertung der Investitionskosten (CAPEX) von dynamischen optischen Netzen. Es werden die wichtigsten Kostenfaktoren und die Beziehung zwischen den Kosten und der Performanz des Netzes analysiert. Die Leistungsfähigkeit aller in der Arbeit vorgeschlagenen Verfahren sowie die Genauigkeit des analytischen Modells zur Bestimmung der Verbindungsaufbauzeit wird durch umfangreiche Simulationen nachgewiesen. / Conventional optical transport networks have leveraged the provisioning of high-speed connectivity in the form of long-term installed, constant bit-rate connections. The setup times of such connections are in the order of weeks, given that in most cases manual installation is required. Once installed, connections remain active for months or years. The advent of grid computing and cloud-based services brings new connectivity requirements which cannot be met by the present-day optical transport network. This has raised awareness on the need for a changeover to dynamic optical networks that enable the provisioning of bandwidth on demand (BoD) in the optical domain. These networks will have to serve connections with different bit-rate requirements, with random interarrival times and durations, and with stringent setup latencies. Ongoing research has shown that grid computing and cloud-based services may in some cases request connections with holding times ranging from seconds to hours, and with setup latencies that must be in the order of milliseconds. To provide BoD, dynamic optical networks must perform connection setup, maintenance and teardown without manual labour. For that, software-configurable networks are needed that are deployed with enough capacity to automatically establish connections. Recently, network architectures have been proposed for that purpose that embrace flex-grid wavelength division multiplexing, reconfigurable optical add/drop multiplexers, and bandwidth variable and tunable transponders as the main technology drivers. To exploit the benefits of these technologies, online resource allocation methods are necessary to ensure that during network operation the installed capacity is efficiently assigned to connections. As connections may arrive and depart randomly, the traffic matrix is unknown, and hence, each connection request submitted to the network has to be processed independently. This implies that resource allocation must be tackled as an online optimization problem which for each connection request, depending on the network state, decides whether the request is admitted or rejected. If admitted, a further decision is made on which resources are assigned to the connection. The decisions are so calculated that, in the long-run, a desired performance objective is optimized. To achieve its goal, resource allocation implements control functions for routing and spectrum allocation (RSA), connection admission control (CAC), and grade of service (GoS) control. In this dissertation we tackle the problem of online resource allocation in dynamic optical networks. For that, the theory of Markov decision processes (MDP) is applied to formulate resource allocation as an online optimization problem. An MDP-based formulation has two relevant advantages. First, the problem can be solved to optimize an arbitrarily defined performance objective (e.g. minimization of blocking probability or maximization of economic revenue). Secondly, it can provide GoS control for groups of connections with different statistical properties. To solve the optimization problem, a fast, adaptive and state-dependent online algorithm is proposed to calculate a resource allocation policy. The calculation is performed recursively during network operation, and uses algorithms for RSA and CAC. The resulting policy is a course of action that instructs the network how to process each connection request. Furthermore, an implementation of the method is proposed that uses a 3-way handshake protocol for connection setup, and an analytical performance evaluation model is derived to estimate the connection setup latency. Our study is complemented by an evaluation of the capital expenditures of dynamic optical networks. The main cost drivers are identified. The performance of the methods proposed in this thesis, including the accuracy of the analytical evaluation of the connection setup latency, were evaluated by simulations. The contributions from the thesis provide a novel approach that meets the requirements envisioned for resource allocation in dynamic optical networks.

La croissance continue du trafic Internet implique une augmentation de la consommation d'énergie en raison des nombreuses conversions optique à électronique(OEO) requises par les routeurs et les commutateurs. L'utilisation de réseaux transparents pourraient freiner cette croissance incontrôlée, mais le maintien des données dans le domaine optique a deux conséquences néfastes: une accumulation du bruit et des non-linéarités de l'amplification qui dégrade fortement les performances au niveau de la couche physique. et la contrainte de continuité de longueur d'onde (WCC) reflétant la conservation de la longueur d'onde du signal optique dans les réseaux optiques multiplexés en longueur d'onde (WDM) qui dégradent les performances du réseau, notamment sa probabilité de blocage. Les convertisseurs de longueur d'onde (WC) peuvent pallier la contrainte WCC, mais les seuls dispositifs suffisamment matures disponibles dans le commerce sont les WC basés sur OEO (OEO-WC). Cependant, leur coût augmente avec les débits binaires. D'autre part, des convertisseurs de longueur d'onde tout optique (AO-WC) ont été démontrés dans des laboratoires de recherche, avec toutefois une plage de conversion limitée et une dégradation du signal converti.Dans cette thèse, nous concevons la couche de transmission en utilisant deux ensembles de formats de modulation différents avec des plages de débits différentes; et par conséquent différents modèles d'estimation de performance. Au niveau du réseau, nos analyses montrent que la contribution des WC dépend des demandes de trafic servant à l’ordre dans un scénario de planification du réseau; qu'en utilisant des algorithmes fixed-alternate-routing (FAR) ou least-loaded-routing (LLR) et un algorithme d'affectation de longueur d'onde first-fit (FF), les AO-WCs offrent les mêmes améliorations de performances que les OEO-WC. De plus, nous identifions une plage de conversion et une cascadabilité optimale d’AO-WC qui montre que le LLR nécessite un nombre de conversions par canal inférieur au FAR. / The continuous growth of Internet traffic implies an increased power consumption due to the many optical-to-electronic (OEO) conversions required by routers and switches. Transparent networks could curb this uncontrolled growth, but keeping the data in the optical domain has two adverse consequences: physical layer impairments accumulation which strongly degrades the performance due to amplication noise and non-linearities; and the wavelength continuity constraint (WCC) to keep the opticalsignal's wavelength unchanged in wavelength-division-multiplexed (WDM) optical networks which degrades network blocking performance. Wavelength converters (WCs) can alleviate the WCC constraint, but the only commercially available devices are the OEO-based WCs (OEO-WCs), however, their cost increases with bit-rates. On the other hand, all-optical wavelength converters (AO-WCs) have been demonstrated in research laboratories albeit with a limited conversion range and a performance that degrades converted signal's quality.In this thesis, we design the transmission layer using two different modulation formats sets with different bit-rates ranges; and consequently different performance estimation models. At the network level, our analyses show that WCs' contribution depends on traffic demands serving ordering in the online traffic assumption; that using xed-alternate routing (FAR) or least-loaded routing (LLR) algorithms and first-fit (FF) wavelength assignment algorithm, AO-WCs give the same performance enhancement as OEO-WCs. Moreover, we identify an optimum AO-WC conversion range and cascadability which shows that LLR requires lower number of conversions per channel compared to FAR.