Regenerative vectorial breathers in a delay-coupled neuromorphic microlaser with integrated saturable absorber

TL;DR

This paper investigates polarization dynamics in a delay-coupled micropillar laser with an integrated saturable absorber, revealing vectorial breathers and polarization mode competition relevant for polarized pulse sources and neuro-inspired computing.

Contribution

It demonstrates the experimental observation of vectorial breathers in polarization angle and provides a numerical model explaining polarization mode competition due to symmetry-breaking bifurcations.

Findings

Observation of polarization angle modulation without total intensity change.

Numerical model reproduces experimental polarization dynamics.

Identification of regimes based on polarization anisotropy and pump parameters.

Abstract

We report on the polarization dynamics of regenerative light pulses in a micropillar laser with integrated saturable absorber coupled to an external feedback mirror. The delayed self-coupled microlaser is operated in the excitable regime, where it regenerates incident pulses with a supra-threshold intensity -- resulting in a pulse train with inter-pulse period approximately given by the feedback delay time, in analogy with a self-coupled biological neuron. We report the experimental observation of vectorial breathers in polarization angle, manifesting themselves as a modulation of the linear polarized intensity components without significant modulation of the total intensity. Numerical analysis of a suitable model reveals that the observed polarization mode competition is a consequence of symmetry-breaking bifurcations induced by polarization anisotropy. Our model reproduces well the observed experimental results and predicts different regimes as a function of the polarization anisotropy parameters and the pump parameter. We believe that these findings are relevant for the fabrication of flexible sources of polarized pulses with controlled properties, as well as for neuroinspired on-chip computing applications, where the polarization may be used to encode or process information in novel ways.