Modulational instability and nonlocality management in coupled NLS system

TL;DR

This paper analyzes how nonlocality affects modulational instability in coupled nonlinear Schrödinger systems, showing that nonlocality can suppress instability growth and enable stability management in wave interactions.

Contribution

It provides a comprehensive analytical and numerical study of nonlocality's role in stabilizing coupled NLS waves and introduces a geometrical approach for nonlocality management.

Findings

Nonlocality significantly reduces instability growth rate.

Nonlocality broadens the stable regime for wave interactions.

Geometrical analysis enables stability control in nonlocal media.

Abstract

The modulational instability of two interacting waves in a nonlocal Kerr-type medium is considered analytically and numerically. For a generic choice of wave amplitudes, we give a complete description of stable/unstable regimes for zero group-velocity mismatch. It is shown that nonlocality suppresses considerably the growth rate and bandwidth of instability. For nonzero group-velocity mismatch we perform a geometrical analysis of a nonlocality management which can provide stability of waves otherwise unstable in a local medium.