The Benefit of Split Nonlinearity Compensation for Optical Fiber Communications

TL;DR

Dividing digital nonlinearity compensation between transmitter and receiver in optical fiber communications enhances transmission capacity and SNR, especially over long distances, as confirmed by theoretical analysis and numerical simulations.

Contribution

This paper demonstrates that split nonlinearity compensation consistently outperforms single-sided approaches in fiber optic systems, supported by the Gaussian noise model and simulation results.

Findings

Split compensation yields approximately 1 bit increase in mutual information over 2000 km.

Theoretical SNR gain of 1.5 dB for long-distance, high-bandwidth transmission.

Split compensation is beneficial for systems with multiple fiber spans.

Abstract

In this Letter we analyze the benefit of digital compensation of fiber nonlinearity, where the digital signal processing is divided between the transmitter and receiver. The application of the Gaussian noise model indicates that, where there are two or more spans, it is always beneficial to split the nonlinearity compensation. The theory is verified via numerical simulations, investigating transmission of single channel 50 GBd polarization division multiplexed 256-ary quadrature amplitude modulation over 100 km standard single mode fiber spans, using lumped amplification. For this case, the additional increase in mutual information achieved over transmitter- or receiver-side nonlinearity compensation is approximately 1 bit for distances greater than 2000 km. Further, it is shown, theoretically, that the SNR gain for long distances and high bandwidth transmission is 1.5 dB versus transmitter- or receiver-based nonlinearity compensation.