Theoretical and experimental comparison for the characteristics of quantum cascaded lasers

Quantum cascaded lasers (QCLs) have many advantages compared with other types of semiconductor-based sources. Therefore, it is important to evaluate their characteristics theoretically. In this paper our aim is to develop a simple algorithm for this interesting type of sources. This algorithm describes a non-trivial evaluation of the most important characteristics. It is used to calculate the output power, threshold current density, slope efficiency and differential efficiency as a function of the structural parameters. Moreover, it explains some features of QCLs characteristics observed experimentally. The calculated dependences are in good agreement with available published experimental data. On the other hand, the optimization of the characteristics of these sources is of primary concern. In this paper we also include a method for this optimization in order to realize the potential advantages of QCLs.