Investigation of optical gain in AlGaAs/GaAs symmetric double semi-parabolic quantum well laser

In this paper, the optical gain in symmetric double semi-parabolic quantum well laser is calculated for typical GaAs/Al_xGa_1-xAs. For this purpose, numerical solution of the Schrödinger equation is done in order to obtain the energy levels and their corresponding wave functions of electrons and holes in double semi-parabolic quantum well. Results are used to obtain the optical gain of this nanostructure. The effects of material parameters such as thickness of the barrier and width of the wells, Al composition and density of the carriers as well as external parameters such as temperature and pressure on the optical gain coefficient are investigated. Numerical results clearly show that by increasing of carrier concentration, wells width and decreasing the thickness of barrier, temperature and pressure the optical gain increases. Finally, we introduce the optimum structure of quantum well to obtain the maximum optical gain, which can be useful for quantum well laser designing.