Feedback induced locking in semiconductor lasers with strong amplitude-phase coupling

TL;DR

This paper investigates how optical feedback induces locking effects in quantum-dot semiconductor lasers with strong amplitude-phase coupling, combining theoretical modeling and experimental validation to understand pulsed-like outputs and bifurcation behaviors.

Contribution

It introduces a new theoretical model for feedback-induced locking in quantum-dot lasers and validates it with experimental results, revealing how laser parameters influence oscillation behaviors.

Findings

Feedback can induce periodic pulsed outputs in quantum-dot lasers.

A new model accurately reproduces experimental observations.

Oscillation frequency staircase behavior is linked to bifurcation reordering.

Abstract

The influence of optical feedback on semiconductor lasers has been a widely studied field of research due to fundamental interests as well as the optimization of optical data transmission and computing. Recent publications have shown that it is possible to induce a periodic pulsed like output in quantum-dot and quantum-well laser diodes utilizing the locking of the external cavity modes and the relaxation oscillation frequency. We present an in-depth analysis of this effect. We choose submonolayer quantum dots as a gain system, as these provide a relatively strong amplitude-phase coupling, which has proven to be very beneficial for these locking effects to occur. Introducing a new theoretical model we can correctly reproduce the essential features of the gain system and validate them by comparison to our experimental results. From this starting point we can further explore how the staircase behavior of the oscillation frequency with increasing pump current can be influenced by changing various laser parameters. The staircase behavior is induced by a reordering of the Hopf bifurcations giving birth to the regular pulsed-like oscillations.