Cavity solitons in vertical-cavity surface-emitting lasers

TL;DR

This paper studies how delay feedback can induce and control spontaneous motion of localized light structures in VCSELs, combining experimental evidence with analytical modeling to understand the parameters influencing their dynamics.

Contribution

It provides the first experimental demonstration of stationary localized structures in VCSELs and develops an analytical framework for their motion under delay feedback.

Findings

Delay feedback induces spontaneous motion of localized structures.

Phase of feedback and carrier lifetime significantly influence dynamics.

Derived analytical formulas for drift instability threshold and structure velocity.

Abstract

We investigate a control of the motion of localized structures of light by means of delay feedback in the transverse section of a broad area nonlinear optical system. The delayed feedback is found to induce a spontaneous motion of a solitary localized structure that is stationary and stable in the absence of feedback. We focus our analysis on an experimentally relevant system namely the Vertical-Cavity Surface-Emitting Laser (VCSEL). In the absence of the delay feedback we present experimental evidence of stationary localized structures in a 80 $\mu$m aperture VCSEL. The spontaneous formation of localized structures takes place above the lasing threshold and under optical injection. Then, we consider the effect of the time-delayed optical feedback and investigate analytically the role of the phase of the feedback and the carrier lifetime on the self-mobility properties of the localized structures. We show that these two parameters affect strongly the space time dynamics of two-dimensional localized structures. We derive an analytical formula for the threshold associated with drift instability of localized structures and a normal form equation describing the slow time evolution of the speed of the moving structure.