Density Matrix Simulations of Quantum Cascade Lasers: Optical and Microwave Dynamics

We discuss a self-consistent simulation approach for the dynamic modeling of quantum cascade lasers (QCLs). These feature a quantum-engineered active region, enabling unique functionalities such as frequency comb generation in the midinfrared and terahertz range. The model combines a density matrix description of the active region with electromagnetic modeling of the microwave and optical propagation in the laser waveguide. Based on simulations of experimental QCL structures, we demonstrate the accuracy and numerical efficiency of the model. Due to its versatility, the approach can be adapted to different waveguide configurations and also to other quantum optoelectronic devices.