Cross-phase modulation influence on a two-channel optical PSK homodyne transmission system

The residual amplitude modulation of adjacent channels causes cross-phase modulation which is responsible for degradation in the error rate performance of a phase detection system. This influence on a two-channel 10 Gb/s optical phase-shift-keying (PSK) homodyne transmission system was experimentally evaluated. A penalty was observed for more than 6 dBm fiber input power with 28% residual amplitude modulation passing through a 100 km dispersion shifted-fiber. Since cross-phase modulation does not require phase matching, which is required for four-wave mixing, the optical frequency range in which the influence occurs is broadband. These results show that residual amplitude modulation in synchronous optical frequency division multiplexing transmission systems severely limits the fiber input power.<>