A generalized Haus master equation model for mode-locked class-B lasers

TL;DR

This paper introduces a generalized Haus master equation for class-B lasers that captures both slow and fast gain dynamics, enabling the analysis of various instabilities and harmonic mode-locking behaviors.

Contribution

A novel generalized model that extends the classical Haus equation to include fast gain dynamics and predicts new instability regimes in mode-locked lasers.

Findings

Model describes Q-switched instability

Predicts leading edge instability

Explains harmonic mode-locking emergence

Abstract

Using an asymptotic technique we develop a generalized version of class-B Haus partial differential equation mode-locking model that accounts for both the slow gain response to the averaged value of the field intensity and the fast gain dynamics on the scale comparable to the pulse duration. We show that unlike the conventional class-B Haus mode-locked model, our model is able to describe not only Q-switched instability of the fundamental mode-locked regime, but also the leading edge instability leading to harmonic mode-locked regimes with the increase of the pump power.