Analysis of the four-wave mixing impact on the most heavily affected channels of dense and ultra-dense wavelength division multiplexing systems using non-zero dispersion shifted fibers

In this paper, the impact of four-wave mixing (FWM) phenomenon on the system performance has been analyzed via focusing on effects of FWM products falling into the center channels, i.e. the most heavily affected ones among all, of equally spaced 9-, 11-, 13- and 15-channel DWDM systems having channel spacing values of 12.5 GHz, 25 GHz, 50 GHz and 100 GHz, and UDWDM systems having 6.25 GHz channel spacing value. DWDM and UDWDM systems using four different single-span commercially available NZDSFs, i.e. TeraLight™, LEAF®, TrueWave®-Reach and TrueWave®-RS, have been considered in simulations. Results show that for all NZDSF types, input powers even as low as 1 mW do not satisfy a minimum 23 dB signal-to-crosstalk ratio (SXR) criterion in UDWDM and DWDM systems using 6.25 GHz and 12.5 GHz channel spacing values, respectively. Furthermore, for all DWDM and UDWDM systems, the lowest and the highest FWM crosstalk values belong to the TeraLight and the TrueWave-RS fibers, respectively, at all input powers, channel numbers and channel wavelengths while the minimum and the maximum SXR variations with varying channel wavelengths are obtained in the TrueWave-Reach and the LEAF fibers, respectively.