Mode-locking induced by coherent driving in fiber lasers

TL;DR

This paper proposes a theoretical method for achieving stable mode-locking in fiber lasers through coherent driving, leading to phase-locked pulses and potentially simplifying pulse generation without complex intracavity mechanisms.

Contribution

It introduces a novel approach where injecting a detuned signal induces mode-locking, resulting in phase-locked pulses similar to cavity solitons, expanding understanding of laser dynamics.

Findings

Phase-locked pulses exist over a wide parameter range.

Laser acts as a passive resonator due to non-instantaneous gain saturation.

Coherent driving can induce stable mode-locking in fiber lasers.

Abstract

The generation of stable short optical pulses in mode-locked lasers is of tremendous importance for many applications. Mode-locking is a broad concept that encompasses different processes enabling short pulse formation. It typically requires an intracavity mechanism that discriminates between single and collective mode lasing, which can be complex and sometimes adds noise. Moreover, known mode-locking schemes do not guarantee phase stability of the carrier wave. Here we theoretically propose that injecting a detuned signal seamlessly leads to mode-locking in fiber lasers. We show that phase-locked pulses, akin to cavity solitons, exist in a wide range of parameters. In that regime the laser behaves as a passive resonator due to the non-instantaneous gain saturation.