Optimal dispersion management for wavelength-division-multiplexed RZ optical pulse transmission

The frequency shift induced by cross-phase modulation between different channels can be reduced by dispersion management in a wavelength-division-multiplexed (WDM) optical transmission system in RZ format. The reduction is increased for larger dispersion difference in a lossless two-step dispersion managed line. However, in the presence of fibre loss and lumped amplifiers, the frequency shift tends to increase for a large dispersion difference in which a stable pulse with the same initial pulsewidth requires higher enhanced power than for the lossless case. Optimal dispersion management schemes in WDM systems are also proposed.