# Mode-locking in vertical external-cavity surface-emitting lasers with type-II quantum-well configurations

## TL;DR

This paper presents a numerical study of mode-locking in vertical external-cavity surface-emitting lasers with type-II quantum wells, identifying conditions for stable 100 fs pulses and proposing design strategies to prevent instability.

## Contribution

It introduces a microscopic model for mode-locking in type-II quantum well VECSELs and suggests design strategies to achieve stable ultrashort pulses.

## Key findings

- Stable mode-locked pulses in the 100 fs range identified.
- Design strategies to avoid unstable pulse dynamics proposed.
- Numerical solutions of Maxwell-semiconductor Bloch equations demonstrated.

## Abstract

A microscopic study of mode-locked pulse generation is presented for vertical external-cavity surface-emitting lasers utilizing type-II quantum well configurations. The coupled Maxwell semiconductor Bloch equations are solved numerically where the type-II carrier replenishment is modeled via suitably chosen reservoirs. Conditions for stable mode-locked pulses are identified allowing for pulses in the \unit[100]{fs} range. Design strategies for type-II configurations are proposed that avoid potentially unstable pulse dynamics.