Modeling and computational analysis of the combined impact of optical Kerr nonlinearities on the performance of DWDM long-haul communication systems

Nonlinear impacts arising from Kerr effect cause crucial limitations in the performance of optical communication systems. The combined impact of SPM, XPM and FWM in WDM-based communication systems has rarely been focused on with experimental or numerical methods because of complicated nature of optical nonlinear phenomena, modeling complexity, limitations on testing equipment and difficulties in performing measurements over long distances. Furthermore, in limited number of papers concentrating on the combined impact of SPM, XPM and FWM in WDM-based systems, total impact has generally been determined by summation of results obtained from individual impacts of SPM, XPM and FWM. Thus, the interplay among SPM, XPM and FWM has often been neglected. In this paper, the combined impact of SPM, XPM and FWM in DWDM long-haul communication systems has been modeled and computationally analyzed. Variations of signal-to-crosstalk ratio (SXR) with input powers of channels and channel spacings under the combined impact of SPM, XPM and FWM and the single impact of FWM have been observed and compared. Comparison of research results with results of former studies has also been presented. Research results show that combined impact of SPM, XPM and FWM is significant below 100 GHz channel spacings for input powers of 3 mW and 5 mW, below 50 GHz channel spacings for 1 mW input powers and below 30 GHz channel spacings for 0.5 mW input powers. For input powers of 0.1 mW, instead of the combined impact of SPM, XPM and FWM, single impact of FWM can be considered.