Step-size distribution strategies in SSFM simulation of DWDM links

Brief review of methods used for simulation of signal propagation in Wavelength-Division-Multiplexed (WDM) links is presented. Step-size distribution strategies used in Symmetrized-Split-Step-Fourier-Method (S-SSFM) are analysed. We propose novel Modified Logarithmic (ML S-SSFM) method of step-size distribution, which is a generalisation of logarithmic method used to suppress spurious FWM tones. In ML S-SSFM the slope of logarithmic step-size distribution is optimised by performing several pre-simulations of averaged optical field. Overall time savings exceed 50%, comparing with walk-off method. In is also more efficient than recently published method in which step-size is inversely proportional to the cube root of instantaneous signal power.