Near-threshold relaxation dynamics of a quantum dot laser

The near-threshold dynamics of a QD and a commercial QW laser are investigated both experimentally and theoretically. Below threshold, the resonance frequency and damping factor of the QD laser exhibit a different behaviour as compared to the QW counterpart. In the near-threshold regime, the intra-dot carrier relaxation is predicted from an empirical pair-states model to have a strong impact on the QD laser's modulation dynamics. The widespread of experimental values for the damping factor reported in the literature for QD lasers is a further indication that this empirical approach is pushed to the limits in this situation. More accurate microscopic modelling should rely on a separation of electron and hole dynamics.