System degradation due to multipath coherent crosstalk in WDM network nodes

This paper shows-both experimentally and through Monte Carlo simulation-that in wavelength division multiplexing (WDM) lightwave networks coherent crosstalk in network nodes causes multipath fading on a seconds to minutes time scale. The result of such fading is that the bit error rate (BER) fluctuates significantly as a function of time. We find that for eight crosstalk paths a signal-to-crosstalk ratio (SXR) greater than 40 dB is required to make this fading negligible, The simulation also shows that for 32 crosstalk paths an SXR as much as 55 dB is required to combat the crosstalk penalty.