Numerical simulation of multi-channel WDM transmission system in non-linear optical fiber communication system

Numerical simulations are of great importance in the study and design of the optical wavelength division multiplexing (WDM) system. In this paper, three kinds of nonlinear phenomena in fibers, which are known as self-phase modulation (SPM), cross-phase modulation (XPM) and four-wave-mixing (FWM), are numerically investigated. In the study, the spacing frequency of 200 GHz for the channel is adopted for all the four laser sources. Also, the light wave is externally modulated by a pseudorandom electric signal of 40 GHz. The infinite-differential method is used for the solving of the nonlinear Schrodinger equation (NLSE) and Gaussian white noise is also taken into consideration. It is proved by the simulation results that high optical power of laser sources can incur serious nonlinear interference in fibers. It is also shown that the dispersion compensation effect can be achieved over 100 km span. The simulation results prove that the model is effective in WDM system performance evaluation.