Localized structures in broad area VCSELs: experiments and delay-induced motion

TL;DR

This paper explores the experimental and theoretical dynamics of localized light structures in broad area VCSELs, focusing on how delay feedback induces motion and how various parameters influence this behavior.

Contribution

It provides the first experimental evidence of stationary localized structures in VCSELs and develops a mean field model to analyze delay-induced motion and bifurcation behavior.

Findings

Delay feedback causes spontaneous motion of localized structures.

Motion threshold and velocity depend on feedback parameters and phase.

Theoretical model predicts influence of phase and carrier relaxation on LS dynamics.

Abstract

{We investigate the space-time dynamics of a Vertical-Cavity Surface-Emitting Laser (VCSEL) subject to optical injection and to delay feedback control. Apart from their technological advantages, broad area VCSELs allow creating localized light structures (LSs). Such LSs, often called Cavity Solitons, have been proposed to be used in information processing, device characterization, and others. After a brief description of the experimental setup, we present experimental evidence of stationary LSs. We then theoretically describe this system using a mean field model. We perform a real order parameter description close to the nascent bistability and close to large wavelength pattern forming regime. We theoretically characterize the LS snaking bifurcation diagram in this framework. The main body of this chapter is devoted to theoretical investigations on the time-delayed feedback control of LSs in VCSELs. The feedback induces a spontaneous motion of the LSs, which we characterize by computing the velocity and the threshold associated with such motion. In the nascent bistability regime, the motion threshold and the velocity of moving LSs depend only on the feedback parameters. However, when considering the previously introduced mean-field model, theoretical predictions indicate that both motion threshold and velocity are strongly affected by the phase of the delay and by the carrier relaxation rate.