Finite-Difference Time-Domain Simulation of Mid- and Far-Infrared Quantum Cascade Lasers

We present simulations of mid- and far-infrared quantum cascade lasers operating with/without external magnetic field. Maxwell-Bloch solver based on the finite-difference time-domain method was used in our investigation. Reduction of the far-infrared quantum cascade laser emission intensity is associated with increased optical losses in highly doped layers when magnetic field is changed from 4.2 T to 6.2 T. A simulated emission spectrum of mid-infrared disc-shaped quantum cascade laser with 60μm radius is consistent with the experimentally observed irregular spacing between quantum cascade laser emission lines.