Modeling of the Impact of Nonlinear Propagation Effects in Uncompensated Optical Coherent Transmission Links

On the Accuracy of the Gaussian Nonlinear Model for Dispersion-unmanaged Coherent Links

“…The recently discovered quasi-Gaussian nature of the statistics of the nonlinear interference (NLI) in dispersion unmanaged (DU) coherent optical links with single-carrier modulations stimulated the development of several analytical models to evaluate the variance of the NLI [1][2][3] , and of elementary bit error rate (BER) formulas based on the received signal to noise ratio (SNR) 4,5 . In this scenario, the Gaussian nonlinear (GN) model 1,6,7 is particularly attractive, since it is able to provide a simple analytical formula for the NLI power spectral density (PSD).…”

“…In this scenario, the Gaussian nonlinear (GN) model 1,6,7 is particularly attractive, since it is able to provide a simple analytical formula for the NLI power spectral density (PSD). The common assumption shared by all the above models is that nonlinearity is a small perturbation of the nonlinear Schrödinger equation (NLSE).…”

“…The common assumption shared by all the above models is that nonlinearity is a small perturbation of the nonlinear Schrödinger equation (NLSE). The extra peculiar assumption of the GN model is that the input modulated signal is a Gaussian stochastic process 1,7,8 . In this work we wish to add to the debate on the accuracy of the GN model.…”

Analysis of Nonlinear Signal Interference to Optimize the Coherent Optical Transmission System

“…Moreover, the commercial optical simulator software is expensive and simulation running output takes longer time [6]. Consequently, GN model is the way and method to determine the power of nonlinear signal interference ( NLSI p ) [7][8][9]. In GN model, we control the total number of spans causing variation to the link length randomly [10].…”

“…A noise figure of 5dB compensates the link loss depending on the fiber loss coefficient and span length.The p NLSI is determined at the input of the EDFA and the P ASE is observed at the output of the EDFA [15] in the optical link of the COTS as shown in Fig. 1 [9].In this condition 27 WDM comb are considered where 193.4145 THz is the center channel frequency within the range from 192.7645 THz to 194.0645 THz. These channel frequencies create odd and even number of channels with 0.05THz spacing .The simulation is performed for 5000 km silica fiber link distance considering 128Gb/s and 256Gb/s .We analyze the GN models for different modes and conditions to predict the accuracy among the models.…”