Wavelength reconfigurability for next generation optical access networks

Next generation optical access networks should not only increase the capacity but also be able to redistribute the capacity on the fly in order to manage larger variations in traffic patterns. Wavelength reconfigurability is the instrument to enable such capability of network-wide bandwidth redistribution since it allows dynamic sharing of both wavelengths and timeslots in WDM-TDM optical access networks. However, reconfigurability typically requires tunable lasers and tunable filters at the user side, resulting in cost-prohibitive optical network units (ONU). In this dissertation, I propose a novel concept named cyclic-linked flexibility to address the cost-prohibitive problem. By using the cyclic-linked flexibility, the ONU needs to switch only within a subset of two pre-planned wavelengths, however, the cyclic-linked structure of wavelengths allows free bandwidth to be shifted to any wavelength by a rearrangement process. Rearrangement algorithm are developed to demonstrate that the cyclic-linked flexibility performs close to the fully flexible network in terms of blocking probability, packet delay, and packet loss. Furthermore, the evaluation shows that the rearrangement process has a minimum impact to in-service ONUs. To realize the cyclic-linked flexibility, a family of four physical architectures is proposed. PRO-Access architecture is suitable for new deployments and disruptive upgrades in which the network reach is not longer than 20 km. WCL-Access architecture is suitable for metro-access merger with the reach up to 100 km. PSB-Access architecture is suitable to implement directly on power-splitter-based PON deployments, which allows coexistence with current technologies. The cyclically-linked protection architecture can be used with current and future PON standards when network protection is required

Redes ópticas passivas avançadas e de cobertura estendida

Mestrado em Engenharia Electrónica e TelecomunicaçõesA grande procura por largura de banda acompanhada pelas preocupações económicas tornaram as Redes Ópticas Passivas o foco das operadoras de telecomunicações. A intensificação dos trabalhos nesta área levou à criação de vários standards e intensificou a investigação na área. Ao longo deste trabalho os requisitos definidos na norma EPON e GPON foram analisados bem como algumas das futuras alternativas. Seguiu-se a caracterização dos sistemas EPON e GPON existentes no laboratório. Finalmente um protótipo para um Reach Extender previamente desenvolvido é analisado e testado tendo em vista provar o seu funcionamento com tráfego GPON.The high demand for bandwidth accompanied by economic worries has made the passive optical networks the focus of telecommunication operators. The intensification of works on this area has led to the creation of several standards and intensified the researches. Throughout the work, the requirements defined in the standard EPON and GPON are analyzed as well as future alternatives. Later, EPON and GPON systems are characterized, and finally a prototype previously developed is adjusted, analyzed and tested in order to prove its operation in GPON