Tolerance to in-band coherent crosstalk of differential phase-shift-keyed signal with balanced detection and FEC

It is found experimentally that the differential phase-shift-keyed (DPSK) signal with balanced detection has /spl sim/6 dB higher tolerance to in-band coherent crosstalk than on-off-keyed (OOK) signal. We attribute the improved crosstalk tolerance of the DPSK signal to its 6-dB lowered peak signal power as compared to the OOK signal for equal bit-error rate in optical signal-to-noise-ratio-limited systems. The impact of signal coherence on the crosstalk tolerance in a 10-Gb/s DPSK system adopting a standard Reed-Solomon forward-error correction is also investigated.