The crosstalk variance of stimulated Raman crosstalk in wavelength-division-multiplexing (WDM) systems is derived analytically in a closed-form formula for all systems with different walkoff length. The probability density function (pdf) of stimulated Raman crosstalk is found to be lognormal distribution (Gaussian distribution in decibel scale). Both power penalty and power limit induced by Raman crosstalk are evaluated and can be applied to single-and multispan WDM systems.
Keang-Po Ho, "Statistical Properties of Stimulated Raman Crosstalk in WDM Systems," J. Lightwave Technol. 18, 915- (2000)