Wideband Gaussian Noise Model of Nonlinear Distortions From Semiconductor Optical Amplifiers

TL;DR

This paper introduces a wideband Gaussian Noise Model for nonlinear distortions in semiconductor optical amplifiers, providing a simple formula for nonlinear noise-to-signal ratio that is validated through simulations.

Contribution

It presents a new closed-form expression for nonlinear noise in SOAs based on the Agrawal model, improving understanding of broadband nonlinear effects.

Findings

The model achieves less than 0.1 dB error when B×τc > 100.

Gain compression increases nonlinear noise by a factor of 1+Pout/Psat.

The closed-form expression accurately predicts nonlinear noise spectral density.

Abstract

A wideband Gaussian Noise Model of the nonlinear noise power spectral density is developed for a single semiconductor optical amplifier as described by the Agrawal model. A simple, interpretable closed-form expression is obtained for the nonlinear noise-to-signal ratio of broadband wavelength-division multiplexed signals as a function of the Agrawal model parameters, the amplifier output power and the transmission bandwidth. The accuracy of the closed-form expression and its region of validity are assessed in numerical simulations. The error is smaller than 0.1 dB when the product of bandwidth and gain recovery time $B\times\tau_c$ exceeds 100. A complete treatment of gain compression is shown to enhance nonlinear noise by a factor $1+P_\text{out}/P_\text{sat}$ compared to the first-order perturbation theory result.