Performance optimization using advanced modulation formats in WDM metropolitan area networks

This work focuses on the study of advanced modulation formats for enhanced performance and improved cost efficiency metropolitan area networks (MANs). More specifically, a variety of 10 Gbit/s WDM systems appropriate for MANs, including simple point-to-point links and cascades of optical add/drop multiplexers in linear or ring configurations, are investigated. Their performance is evaluated in detail in terms of their tolerance to linear impairments, such as optical signal-to-noise ratio degradation, dispersion, filter concatenation, inter-band and intra-band crosstalk, introduced due to transmission over fiber, as well as the presence of elements, such as terminal equipment and optical add/drop multiplexers, in the network. An important part of this study deals with the optimization of the operating parameters of the system and the component specifications. However, significant attention is also paid to the interplay of the various impairments and the identification of suitable designs and trade-offs to ensure optimized system performance. This detailed study shows that some of the advanced modulation formats proposed are very tolerant to linear impairments and exhibit superior performance compared to conventional NRZ solutions.