Time domain travelling wave model for simulation of passive mode locking in semiconductor quantum dot lasers

The authors implemented a new finite difference time domain travelling wave (TDTW) model for quantum dot (QD) lasers able to treat both the QD ground states (GSs) and excited states (ESs) contributions to the gain and refractive index change and to properly describe the carrier dynamics in the saturable absorber section as a function of the applied reverse bias. The response of the QDs to the electromagnetic field is implemented in time domain as a numerical filter applied at each time step in each longitudinal slice of the cavity. A small set of rate equations modelling carrier dynamics in the GS, ES, wetting layer (WL) and SCH is considered.