Accumulation of nonlinear interference noise in fiber-optic systems

Abstract

Through a series of extensive system simulations we show that all of the previously not understood discrepancies between the Gaussian noise (GN) model and simulations can be attributed to the omission of an important, recently reported, fourth-order noise (FON) term, that accounts for the statistical dependencies within the spectrum of the interfering channel. We examine the importance of the FON term as well as the dependence of NLIN on modulation format with respect to link-length and number of spans. A computationally efficient method for evaluating the FON contribution, as well as the overall NLIN power is provided.

A Simple and Effective Closed-Form GN Model Correction Formula Accounting for Signal Non-Gaussian Distribution

“…The XPM analytical formulas have been used in [18] to generate various results which appear to be in general qualitative agreement with the simulative results of [15]. Such results also confirmed the dependence of non-linearity generation on the fourth moment of the signal constellation, that other groups found within different modeling approaches [20]- [21].…”

Experimental Characterization of the Time Correlation Properties of Nonlinear Interference Noise

“…The ISI coefficients R (n) l are 2 × 2 matrices, whose elements are determined by the data transmitted over the interfering WDM channels. It has been demonstrated in [1][2][3] that the summation on the righthand-side of (1) accurately accounts for the NLIN that is generated by XPM. The index l in R (n) l represents the ISI order, whereas the superscript (n) points to the (relatively slow) dependence of the ISI matrices on time.…”

“…In recent years, extensive efforts have been invested into the characterization of NLIN and the exploration of methods for its mitigation. An important finding in this context was that the cross-phase-modulation (XPM) component of NLIN (the predominant component in most practical scenarios) can be modeled very accurately as an inter-symbol interference (ISI) process with random and time varying ISI coefficients [1][2][3] . Hence, the characterization of NLIN can be translated into the characterization of the corresponding ISI coefficients.…”

Redes ópticas de longa distância com transceptores de taxa de código variável

“…No entanto, alguns trabalhos recentes [56,29] têm rechaçado algumas hipóteses do modelo GN, como a independência das interferências não-lineares com relação ao formato de modulação e a aproximação da interferência NL como um ruído AWG.…”

“…No entanto, ao longo dos spans seguintes, essa aproximação se torna cada vez mais precisa. Com relaçãoàs hipóteses de transparência ao formato de modulação eàs propriedades Gaussianas do sinal, fatores de correção são apresentados em [29,62]. No entanto, para os objetivos deste trabalho, o modelo GN se mostrou como uma ferramenta satisfatória para a tarefa de realizar análises teóricas do desempenho de sistemas de longa distância.…”