The paper on the enhanced version of the GN model (the EGN model) is now available on Optics Express. The EGN model achieves excellent accuracy in predicting the power of non-linearity interference (NLI) that perturbs each transmitted channel. A version of the same paper that includes extended appendices on formulas derivations can be downloaded from arXiv: download paper with extended appendices from here. The EGN model has no limitations related to transmission format, Baud rate, channel spacing, number of channels, amplification type, span length, fiber dispersion, dual-polarization, etc.
 
It represents a reliable alternative to the standard split-step method to characterize the power of non-linear disturbance on transmission channels. It may constitute in most cases an alternative to Monte-Carlo simulation for analysis, design and research in the field of high-performance coherent optical transmission systems.
 
Further ample EGN model validation, across a wide spectrum of system parameters, can be found here, where a closed-form analytical formula for the correction to apply to turn the GN model into EGN is also proposed.
 
 

Case study

To provide an example of the accuracy of the EGN model, we show a normalized plot of all the cross- and multi-channel non-linearity power (the eta parameter) hitting the center-channel in a 15-channel PM-QPSK link as a function of the number of spans. The fiber is similar to Truewave-RSTM (D=3.8 ps/(nm km)), span length 100 km.
 
Left: 32 GBaud, right, 16 GBaud. Channel spacing 1.05 times the symbol rate.

The EGN model (green solid) is extremely accurate, essentially superimposing with the simulation result (red dashed). GN and XPM are the GN model and the frequency-domain XPM model proposed in [1]. Download the above EGN model papers for more details on these plots.

[1] R. Dar, M. Feder, A. Mecozzi, M. Shtaif, “Properties of Nonlinear Noise in Long, Dispersion-Uncompensated Fiber Links,” Optics Express, vol. 21, no. 22, pp. 25685-25699, Nov. 2013.