Experimental study of four wave mixing in non-zero dispersion fiber

The non-zero dispersion fiber is the result of a trade-off between the standard single-mode fiber (SMF) and the dispersion-shifted fiber (DSF) with zero dispersion at 1.55 /spl mu/m to increase the dispersion limit and, at the same time, reduce four-wave mixing (FWM) effects. However, for extremely dense WDM systems with decreased channel spacing, FWM effects can be significant, even with an optimized dispersion of 1/spl sim/2 ps/nm-km. It is very difficult to analytically calculate the power of FWM along the link with amplification, and few results have been presented on the evolution of FWM in this fiber type, especially in periodically amplified systems. In this paper, experiments are presented that examine FWM generation in a fiber link with periodic amplification. The dependence of FWM on the channel spacing, link lengths, and signal formats are presented.