Impact of four-wave mixing on dispersion-managed frequency-shift-keying dense-wavelength-division-multiplexing system including various light-propagating effects

We describe a semi-analytic model used to deterministically and exactly calculate the variance of degenerate and nondegenerate four-wave mixing (FWM) noises for 128 × 10 Gb∕s return-to-zero fre- quency-shift-keying dispersion-managed dense-wavelength-division- multiplexing system. The analytic model includes various important light-propagating effects such as walk-off between channels, oscillation of pulse width with transmission distance, and stochastic variation of bire- fringence strength and orientation along fiber. The achievable maximum Q-factor and allowed maximum input powers for different dispersion man- agement schemes and transmission distances are shown including overall FWM noises from different channel combinations, signal-amplified spon- taneous emission (ASE) beat noise, and others. Achievable maximum transmission distances for such systems are studied. The upper limit of local dispersion of the dispersion map is discussed. In the case of allowed maximum input powers for the system, the variances of overall FWM noise are observed to be about half of those of signal-ASE beat noise when averaged for different transmission distances. It is found that for high- local dispersion, when transmission distance is long enough, effect of non- degenerate FWM noise, compared with degenerate FWM noise, can be ignored. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE) (DOI: 10.1117/1 .OE.52.11.116108)