# Stability Through Asymmetry: Modulationally Stable Nonlinear Supermodes of Asymmetric non-Hermitian Optical Couplers

## TL;DR

This paper investigates the stability of nonlinear supermodes in asymmetric non-Hermitian optical couplers, revealing conditions under which these modes are stable despite unbalanced gain and loss, with implications for photonics applications.

## Contribution

It demonstrates that breaking symmetry in non-Hermitian couplers can produce stable nonlinear supermodes, expanding the design possibilities for photonic devices.

## Key findings

- Stable nonlinear supermodes exist in asymmetric couplers.
- Symmetry breaking can stabilize modes at the PT symmetry point.
- Asymmetric couplers facilitate experimental implementation.

## Abstract

We analyze the stability of a non-Hermitian coupler with respect to modulational inhomogeneous perturbations in the presence of unbalanced gain and loss. At the parity-time (PT) symmetry point the coupler is unstable. Suitable symmetry breakings lead to an asymmetric coupler, which hosts nonlinear supermodes. A subset of those broken symmetry cases finally yields nonlinear supermodes which are stable against modulational perturbations. The lack of symmetry requirements will facilitate experimental implementations and relevant photonics applications.