System physics modeling of the electro-optical energy conversion in mid-infrared quantum cascade lasers

The paper addresses the topic of the electro-optical energy conversion in mid-infrared high power QCL to support designers of optical countermeasure systems in assessing the utility of QCLs for their applications and in specifying the laser sub-system properly. We propose a quadratic dependence of the optical output power on the pump current (L-I curve) in order to reflect the influence of Stark shifting of the energy levels and of heating of the electrons in the planes perpendicular to the current direction. Formulae are given which relate the L-I model parameters to descriptors of these two effects. The model is simple enough to be implemented in system level simulations of the QCL performance in different modes of operations.