An Alternative Approach to the Gaussian Noise Model and its System Implications

Abstract

Abstract-This paper presents an alternative derivation of the Gaussian noise (GN) model of the nonlinear interference (NLI) in strongly dispersive optical systems. The basic idea is to exploit an enhanced regular perturbation expansion of the NLI, which highlights several interesting features of the GN model. Using the framework, we derive a fast algorithm to evaluate the received NLI power spectral density (PSD) for any input PSD. In the paper we also provide an asymptotic expression of the NLI PSD which further speeds up the computation without losing significant accuracy. Moreover, we show how the asymptotic expression can be used to optimize system performance. For instance, we are able to prove why a flat spectrum is best to minimize the NLI variance when the input is constrained to a fixed bandwidth and power. Finally, we also provide a generalization of the NLI GN model to arbitrarily correlated X and Y polarizations.Index Terms-Gaussian Noise (GN) model, perturbation methods.

Regeneration savings in flexible optical networks with a new load-aware reach maximization

“…from node S at coordinate z = 0 to node D at coordinate z = L, with v = f 1 · f 2 , whose expression in absence of dispersion slope is [11,12,17] …”

Perturbative Propagation Models for Coherent Systems

“…For the sake of simplicity, we set the idea in single-polarization and single channel (extensions to WDM and PDM are straightforward). The NLI is an infinite sum of contributions, thus, to get the NLI auto-correlation we need the crosscorrelation between any NLI outgoing paths z and s. Along such paths, relating the input/output correlation across any linear block is just a matter of linear system theory [13]. The challenge regards nonlinear blocks.…”

“…1(right)). Under the key GN-model assumption of a stationary Gaussian input [2], in the alternative GN model derivation [13] it was shown that such a relation takes the remarkably simple form:…”

“…The resulting model was called EGN. By operating instead in the time domain, as in [13], we get the EGN-alternative but equivalent result:…”

Accumulation of nonlinear noise in coherent communication lines without dispersion compensation

“…This nonlinear noise can be described as a Gaussian noise [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], at least in dispersion uncompensated (DU) coherent systems. Gaussian nature of the nonlinear interference (NLI) noise fields is conditioned by Gaussian distribution of the information sampled signal [4][5][6][14][15][16].…”