Stable nonlinear amplification of solitons without gain saturation

TL;DR

This paper introduces a novel method for stable nonlinear amplification of solitons using localized cubic gain in a waveguide with cubic-quintic nonlinearity, eliminating the need for gain saturation and enabling stable soliton amplification.

Contribution

It presents an analytical and numerical demonstration of stable soliton amplification via localized cubic gain without gain saturation in a cubic-quintic nonlinear waveguide.

Findings

Stable spatial solitons supported by localized cubic gain.

Bistability between solitons and zero state.

Potential for nonlinear amplification without gain saturation.

Abstract

We demonstrate that the cubic gain applied in a localized region, which is embedded into a bulk waveguide with the cubic-quintic nonlinearity and uniform linear losses, supports stable spatial solitons in the absence of the quintic dissipation. The system, featuring the bistability between the solitons and zero state (which are separated by a family of unstable solitons), may be used as a nonlinear amplifier for optical and plasmonic solitons, which, on the contrary to previously known settings, does not require gain saturation. The results are obtained in an analytical form and corroborated by the numerical analysis.