Comparison of nonlinear phase noise and intrachannel four-wave mixing for RZ-DPSK signals in dispersive transmission systems

Self-phase-modulation-induced nonlinear phase noise is reduced with the increase of fiber dispersion but intrachannel four-wave mixing (IFWM) is increased with dispersion. Both degrading differential phase-shift keying signals, the standard deviation of nonlinear phase-noise-induced differential phase is about three times that from IFWM even in highly dispersive transmission systems.