Impact of linear and nonlinear crosstalk on the teletraffic performance of WDM optical networks

Abstract

Wavelength routed all-optical networks are a class of backbone wide area networks (WANs) where connections are routed by intermediate nodes in the optical domain without electronic conversion. The performance of these networks are limited by the linear crosstalk introduced by the non-ideal characteristics of the switches, demultiplexers and filters employed in the network nodes. Nonlinear impairments like stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), four-wave mixing (FWM), self phase modulation (SPM) and cross phase modulation (XPM) become significant at higher data rates and/or transmitter power. Previous works have considered the impact of linear impairments while establishing a call in WDM networks. However, the impact of nonlinear impairments has not been considered during the establishment of a call. This work attempts to consider the crosstalk caused by SRS and the linear crosstalk introduced by the optical switches and demultiplexers while establishing lightpaths for dynamically arriving call requests in a 15-node mesh network. Crosstalk leads to poor received signal quality at the destination node. This results in increased receiver bit error rate (BER) thereby degrading the teletraffic performance of the network. A lightpath request is accepted only if the bit error rate (BER) at the destination node is less than 10 -12; otherwise it is rejected