A Simple and Effective Closed-Form GN-Model Correction Formula   Accounting for Signal Non-Gaussian Distribution
  The GN model of non-linear fiber propagation has been shown to overestimate the variance of non-linearity due to the signal Gaussianity approximation, leading to maximum reach predictions for realistic optical systems which may be pessimistic by about 5% to 15%, depending on fiber type and system set-up. Analytical corrections have been proposed, which however substantially increase the model complexity. In this paper we provide a simple closed-form GN model correction formula, derived from the EGN model, which we show to be quite effective in correcting for the GN model tendency to overestimate non-linearity. The formula also permits to clearly identify the correction dependence on key system parameters, such as span length and loss. 
P. Poggiolini, G. Bosco, A. Carena, V. Curri, Y. Jiang, F. Forghieri
physics.optics