Noisy propagation of coherent states in a lossy Kerr medium

TL;DR

This paper analyzes how nonlinear phase noise affects coherent light pulses in lossy Kerr media, revealing limits on information transmission and potential for squeezing, modeled as Gaussian phase diffusion with explicit parameters.

Contribution

It introduces a Gaussian phase diffusion model for nonlinear phase noise in Kerr media, providing explicit formulas and analyzing its impact on information transmission and squeezing.

Findings

Nonlinear phase noise causes irreversibility in Kerr media.

Limits on classical information transmission due to phase noise.

Model can estimate achievable squeezing in lossy Kerr systems.

Abstract

We identify and discuss nonlinear phase noise arising in Kerr self-phase modulation of a coherent light pulse propagating through an attenuating medium with third-order nonlinearity in a dispersion-free setting. This phenomenon, accompanying the standard unitary Kerr transformation of the optical field, is described with high accuracy as Gaussian phase diffusion with parameters given by closed expressions in terms of the system properties. We show that the irreversibility of the nonlinear phase noise ultimately limits the ability to transmit classical information in the phase variable over a lossy single-mode bosonic channel with Kerr-type nonlinearity. Our model can be also used to estimate the amount of squeezing attainable through self- phase modulation in a Kerr medium with distributed attenuation.