Noise induced stabilization of chaotic free-running laser diode

TL;DR

This study demonstrates that spontaneous emission noise can stabilize or destabilize chaotic polarization dynamics in free-running laser diodes, revealing the critical role of cavity birefringence in controlling laser chaos.

Contribution

We theoretically analyze how spontaneous emission noise influences the stabilization of chaos in free-running laser diodes, highlighting the importance of cavity birefringence for experimental control.

Findings

Noise pushes the system over the separatrix, preventing sustained chaos.

A small birefringence value stabilizes the steady-state, affecting chaos stability.

Chaos appears as a transient behavior near the boundary separating attractors.

Abstract

In this paper, we investigate theoretically the stabilization of a free-running vertical-cavity surface-emitting laser exhibiting polarization chaos dynamics. We report the existence of a boundary isolating the chaotic attractor on one side and a steady-state on the other side, and identify the unstable periodic orbit playing the role of separatrix. In addition, we highlight a small range of parameters where the chaotic attractor passes through this boundary, and therefore where chaos only appears as a transient behaviour. Then, including the effect of spontaneous emission noise in the laser, we demonstrate that, for realistic levels of noise, the system is systematically pushed over the separating solution. As a result, we show that the chaotic dynamics cannot be sustained unless the steady-state on the other side of the separatrix becomes unstable. Finally, we link the stability of this steady-state to a small value of the birefringence in the laser cavity and discuss the significance of this result on future experimental work.