Four Wave Mixing (FWM) is a nonlinear process which greatly degrades the performance of the multi-wavelength optical communication systems. This paper describes the analysis of FWM under different all optical modulation formats in two cases of networks such as high nonlinear regime of a 4-Channels, 40 Gb/s WDM network and a normal 32 channel, 40 Gb/s DWDM network. Performance parameters like suppressed FWM side band power, Q-factor and BER are analyzed. Although duobinary, DPSK and DQPSK modulation formats perform better in the latter case, the first case proves that only the DQPSK modulation format performs exceptionally well even in high nonlinear conditions of even DWDM networks.
