Small Chimera States without Multistability in a Globally Delay-Coupled Network of Four Lasers

TL;DR

This paper investigates small chimera states in a four-laser delay-coupled network, revealing their bifurcation routes, stability, and emergence without the need for specially prepared initial conditions.

Contribution

It identifies and characterizes small chimera states in a globally coupled laser network, showing they can be stable solutions without initial condition tuning.

Findings

Small chimera states consist of one synchronized pair and two unsynchronized lasers.

Two classes of small chimeras are identified: bifurcation-related and chaotic regime-based.

Small chimeras can be the only stable solution in certain parameter regions.

Abstract

We present results obtained for a network of four delay-coupled lasers modelled by Lang-Kobayashi-type equations. We find small chimera states consisting of a pair of synchronized lasers and two unsynchronized lasers. One class of these small chimera states can be understood as intermediate steps on the route from synchronization to desynchronization and we present the entire chain of bifurcations giving birth to them. This class of small chimeras can exhibit limit-cycle or quasiperiodic dynamics. A second type of small chimera states exists apparently disconnected from any region of synchronization, arising from pair synchronization inside the chaotic desynchronized regime. In contrast to previously reported chimera states in globally coupled networks, we find that the small chimera state is the only stable solution of the system for certain parameter regions, i.e. we do not need to specially prepare initial conditions.