Reduction of cross-phase modulation-induced impairments in long-haul WDM telecommunication systems via spectral inversion

We study the reduction of cross-phase modulation-induced impairments by the use of spectral inversion in long wavelength-division multiplexed (WDM) optical links which utilize finite-dispersion fiber and standard dispersion compensation in addition to spectral inversion. We show that spectral inversion applied only once, not necessarily near the center of the entire link, significantly reduces the penalties caused by cross-phase modulation. We demonstrate by calculations, for several representative system configurations, Q-factor enhancements of 3-6dB. These enhancements are robust against system nonidealities and asymmetry. Spectral inverters based on LiNbO₃ show particular promise in WDM systems due to their inherently low crosstalk.