Nanosecond-scale discrete wavelength switching in feedback-controlled single-gain-section multi-wavelength lasers

TL;DR

This paper demonstrates nanosecond-scale discrete wavelength switching in integrated multi-wavelength lasers using phase-controlled optical feedback, with potential applications in high-speed optical networking.

Contribution

It introduces a novel method for ultrafast wavelength switching in monolithic InP lasers via feedback phase modulation, supported by experimental and theoretical analysis.

Findings

Switching times below 2.5 ns achieved

Stronger feedback and larger phase modulation speed up switching

Mode coupling influences switching dynamics

Abstract

We investigate discrete wavelength switching in single-gain-section multi-wavelength lasers monolithically integrated on InP with phase-controlled optical-feedback. By modulating the feedback phase, nanosecond-scale wavelength switching is experimentally demonstrated with transition times below 2.5 ns. Measurements consistently show that the switching time decreases with stronger optical feedback and larger phase-modulation amplitudes. Transitions from lower to higher modal gain are faster. We support the experimental observations with a multi-mode extension of the Lang-Kobayashi rate-equation model. We analyze the influence of laser, feedback-cavity, and modulation parameters on the switching dynamics, and highlight the role of mode coupling. These results highlight the potential of integrated multi-wavelength lasers for compact and high-speed all-optical networking systems.