Dependence of XPM Degradation on the Dispersion Map for 10 Gbit/s WDM Links over Standard-Fibre Employing Duobinary Format

The dependence of cross-phase modulation (XPM) -induced degradation on the dispersion map for wavelength division multiplexing (WDM) systems at 10 Gbit/s per channel with 50 GHz of channel spacing and standard single-mode fibre employing duobinary format is investigated through numerical simulation. It is shown that, for low optical power levels at the input of each span and reduced number of spans, the optimum residual dispersion per span is about 150 ps/nm whereas, for higher optical power levels and number of spans, it is about -150 ps/nm. The results suggest that the optimum amount of residual dispersion per span and post-compensation dispersion are almost independent of the pre-compensation dispersion amount. Moreover, the amount of pre-compensation dispersion has a small influence on the XPM-induced degradation.