Modeling of optical gain in quantum cascade laser subjected to strong magnetic field

We present a comprehensive rate equations based model for calculating the optical gain in the active region of quantum cascade laser in magnetic field perpendicular to the structure layers, which takes into account all the relevant carrier relaxation processes. The magnetic field causes electron energy subbands to split into series of discrete Landau levels whose arrangement depends strongly on the magnitude of this field. This enables one to control the population inversion in the active region, and hence the laser output properties, in particular the optical gain. Numerical illustration is provided for a GaAs/AlGaAs based structure, designed to emit radiation in the mid-infrared part of the spectrum.