Analysis of the optical feedback dynamics in InAs/GaAs quantum dot lasers directly grown on silicon

This work reports on a systematic investigation of the influence of optical feedback in InAs/GaAs quantum dot lasersepitaxially grown on silicon. The boundaries associated to the onset of the critical feedback level corresponding to thefirst Hopf bifurcation are extracted at different bias conditions with respect to the onset of the first excited statetransition. Overall, resultsshow that quantum dot lasers directly grown onto silicon are much more resistant to opticalfeedback than quantum well lasers, mostly resulting from a small linewidth enhancement factor of high-quality quantum dot material. However, results also unveil that the onset of the critical feedback level strongly depends on theexcited-to-ground-state ratio, hence a figure of merit showing that a small ratio of the excited-to-ground-state lasingthresholds is not beneficial for maintaining a high degree of stability. This work brings further insights in the understanding of quantum dot laser physics and is useful for designing feedback resistant lasers for isolator-free transmissionin metro, access, and data center optical networks, as well as for integrated photonics.