Spectrally efficient optical fiber communication systems with intensity modulation

In order to efficiently use the available optical bandwidth efforts are under way to achieve spectral efficiencies of at least 0.8 bits/s/Hz. For such spectrally efficient systems (considering co-polarized WDM-channels) the importance of filtering for different modulation formats, different channel bitrates from 10 - 160 Gbit/s and different dispersion map designs will be discussed. It turns out that the optimisation strategy for spectrally efficient WDM systems shows considerable differences to single channel systems. The specific modulation format and the chosen channel bitrate turn out to be of minor importance, thus enabling simple analytic expressions for the achievable system performance.