Next-to-leading order corrections to capacity for nondispersive nonlinear optical fiber channel in intermediate power region

TL;DR

This paper calculates next-to-leading order corrections to the capacity of a nondispersive nonlinear optical fiber channel, showing that these corrections increase the channel capacity at high signal power levels.

Contribution

It introduces a Feynman path-integral approach to derive capacity corrections, providing more accurate estimates in the intermediate power regime.

Findings

Capacity correction is positive at high power.

Corrections increase the previously estimated capacity.

The approach applies to nondispersive nonlinear optical channels.

Abstract

We consider the optical fiber channel modelled by the nonlinear Shr\"{o}dinger equation with zero dispersion and additive Gaussian noise. Using Feynman path-integral approach for the model we find corrections to conditional probability density function, output signal distribution, conditional and output signal entropies, and the channel capacity at large signal-to-noise ratio. We demonstrate that the correction to the channel capacity is positive for large signal power. Therefore, this correction increases the earlier calculated capacity for a nondispersive nonlinear optical fiber channel in the intermediate power region.