Coupled Nonlinear Schr\"odinger System: Role of Four-Wave Mixing Effect on Nondegenerate Vector Solitons

TL;DR

This paper explores how four-wave mixing influences nondegenerate vector solitons in a coupled nonlinear Schrödinger system, revealing breather states and novel collision behaviors relevant for optical light manipulation.

Contribution

It derives new nondegenerate vector soliton solutions in the GCNLS system and uncovers the effects of four-wave mixing on soliton dynamics and collisions.

Findings

Four-wave mixing induces breathing vector solitons.

Nondegenerate solitons exhibit shape-changing collisions.

Degenerate soliton collisions show novel properties.

Abstract

In this paper, we investigate the role of four-wave mixing effect on the structure of nondegenerate vector solitons and their collision dynamics. For this purpose, we consider the generalized coupled nonlinear Schr\"odinger (GCNLS) system which describes the evolution and nonlinear interaction of the two optical modes. The fundamental as well as higher-order nondegenerate vector soliton solutions are derived through the Hirota bilinear method and their forms are rewritten in a compact way using Gram determinants. Very interestingly, we find that the presence of four-wave mixing effect induces a breathing vector soliton state in both the optical modes. Such breather formation is not possible in the fundamental vector bright solitons of the Manakov system. Then, for both strong and weak four-wave mixing effects, we show that the nondegenerate solitons in the GCNLS system undergo, in general, novel shape changing collisions, in addition to shape preserving collision under suitable choice of wave numbers. Further, we analyze the degenerate soliton collision induced novel shape changing property of nondegenerate vector soliton by deriving the partially nondegenerate two-soliton solution. For completeness, the various collision scenarios related to the pure degenerate bright solitons are indicated. We believe that the results reported in this paper will be useful in nonlinear optics for manipulating light by light through collision.