Performance of optically preamplified receivers in WDM systems disturbed by interferometric crosstalk

Interferometric crosstalk is a performance limiting factor of major concern in all-optical WDM transmission networks. Interferometric crosstalk arisin g from performance imperfections in optical components may introduce large power penalties and bit-error rate floors. Optical amplifiers are often use d to increase the signal level incident on a detector so that high receiver sensitivity can be obtained. We investigate theoretically and experimental ly the performance of optically preamplified, direct detection receivers in the presence of interferometric crosstalk. The model includes an accurate description of filtered interferometric crosstalk by using a so-called maxi mum entropy approach. Experimental results, using both directly and externa lly modulated light sources, are found to be in good agreement with theory.