Optimization of high optical gain in type-II In0.70Ga0.30As/GaAs0.40Sb0.60 lasing nano-heterostructure for SWIR applications

Most of the nano-heterostructures exhibiting lasing action in NIR (near infra-red) region that have been modeled and simulated are based on type-I category. The nano-scaled lasing heterostructures, however, of type-II category operating in SWIR (short wave infra-red) region have not been well studied. In this paper, for SWIR generation, an M-shaped type-II In0.70Ga0.30As/GaAs0.40Sb0.60 symmetric lasing nano-heterostructure has been designed. In order to simulate the optical gain, firstly the wave functions associated with conduction and valence sub-bands, carrier densities within the bands, energy band dispersion relations for the quantum well structure, optical matrix elements and finally optical gain have been studied by utilizing the six band k.p method. For the injected carrier concentration of 5 × 1012/cm2, the optimized optical gain within TE mode is as high as ∼9000/cm at the wavelength of ∼1.95 μm, thus providing a very important alternative material system for the generation of SWIR wavelength region.