Optimization of Channel Spacing in WDM Transmission Systems with Dispersion Compensated Links in the Presence of Fiber Nonlinearities

Abstract

The simple expressions appropriate to study the transmission limitations of WDM systems with dispersion compensated links using inline optical amplifiers imposed by fiber nonlinearities are derived in this paper. Two important nonlinear effects, FWM and SRS in the presence of ASE noise are taken into consideration. The maximum possible transmission distance is discussed in terms of various system parameters such as wavelength spacing, number of channels, total bandwidth, etc. Optimum channel spacing to maximize the transmission distance is found as a compromise between conflicting requirements imposed by FWM and SRS in the presence of ASE noise when considered separately. Different dispersion compensation configurations (SMF+DCF, NZDSF -+SMF, NZDSF + +NZDSF -) are discussed in order to find the best one that gives the maximum transmission distance. The optimum channel spacing as a function of number of channels for different dispersion compensation configurations is shown for the first time. The optimum transmission distance, that is the number of amplifier spans, versus the number of channels is also shown.