Error probability of DPSK signals with intrachannel four-wave mixing in highly dispersive transmission systems

A semianalytical method evaluates the error probability of differential phase-shift keying signals with intrachannel four-wave mixing in a highly dispersive fiber link with strong pulse overlap. Depending on initial pulsewidth, the mean nonlinear phase shift of the system can be from 1 to 2 rad for signal-to-noise ratio penalty less than 1 dB. An approximated empirical formula, valid for penalty less than 2 dB, uses the variance of the differential phase of the ghost pulses to estimate the penalty.