Impact of OPC insertion in a WDM link

This paper presents a systematic study on the effectiveness of mid-nonlinearity temporal inversion (MNTI) technique in wavelength division multiplexing (WDM) systems. In WDM systems dispersion slope has a strong impact because it partly affects the efficacy of self-phase modulation (SPM) compensation, and in addition it causes a different shift of the optimum optical phase conjugator (OPC) position for each WDM channel. This slope effect is stronger when a low-dispersion fiber link is considered and in this case significant differences can be found between the various channels of the WDM spectrum. We thus expect that OPC insertion may be more effective in a single mode (SM) fiber WDM system. In a SM link without span-by-span dispersion compensation, a strong walk-off between interacting channels is present and four-wave-mixing is negligible; SPM and cross-phase-modulation (XPM) play a major role as far as nonlinearities (NL).