Impact of FBG feedback phase on laser dynamics

TL;DR

This paper investigates how small thermal-induced phase variations in fiber Bragg gratings affect the chaotic dynamics of semiconductor lasers, revealing significant behavioral changes and stability enhancements.

Contribution

It experimentally demonstrates the impact of feedback phase fluctuations on laser dynamics and aligns findings with an extended Lang-Kobayashi model.

Findings

Phase variations induce significant changes in laser behavior.

Thermal tuning can enhance laser stability periodically.

Qualitative agreement with extended Lang-Kobayashi simulations.

Abstract

Fiber Bragg Gratings have been advantageously used to improve the chaotic properties of semiconductor lasers. Though these components are known to be highly sensitive to environmental conditions, feedback phase fluctuations are often neglected. In this work, we experimentally demonstrate that the small variations of the propagation time induced by a simple thermal tuning of the FBG is sufficient to induce significant changes of the laser behavior. We report periodic stability enhancements linked with phase variations and highlight that both phase variation and phase offsets play an important role. Last, we show a good qualitative agreement with simulations based on an expanded version of the Lang-Kobayashi model.