Simulation of Temperature Dependences of Emission Characteristics of Nano-Layer Injection Lasers Based on Symmetric Heterostructures

The exact problem of electromagnetic wave propagation in a multilayer nanostructure with complex values of dielectric permittivity is solved. The contribution to the refractive index of an additive to the dielectric constant connected with the injected carriers is taken into account. Within the framework of this problem, it is shown that an anomalous temperature dependence of the threshold current of injection lasers based on nanoheterostructures is related to the anti-waveguide action of injected carriers. A quantum-well heterostructure based on InGaAs/AlGaAs/GaAs nanosystems used for fabrication of 0.94-1.14 μm lasers is considered. The applied techniques and approaches are also acceptable for the optimization of multilayer nanostructures based on other solid solutions. As an optical model of the active region of injection lasers based on nanostructures, a planar multilayer dielectric waveguide with complex values of dielectric permittivity in the layers is considered. It is shown that with decreasing thickness of the active region of injection lasers, the dependence of the mode gain on the local gain is essentially sublinear. The reason for this is the antiwaveguide action of electrons. The results of calculations of the temperature dependence of the threshold current of injection lasers indicate the presence of a critical point Tc, at which a sharp decrease in the characteristic temperature occurs. The performed calculations and optimization of the temperature dependence of emission characteristics of injection lasers based on nanostructures show that the anomalous behavior of the temperature dependence of the threshold current is also associated with the weakening of the waveguide properties of theirs active region.