Growth and operation tolerances for Sb-based mid-infrared lasers

Abstract

The potential performance of InAs/InGaSb-based mid-wavelength infrared lasers is examined theoretically. Band structure engineering is employed to determine the superlattice growth parameters which minimize intersubband absorption and Auger recombination losses, resulting in optimized designs which minimize threshold current densities. Calculations are performed to assess the impact of uncertainties in superlattice layer thicknesses and the temperature of laser operation on these optimized laser designs. We find that growth accuracies of ±3.5 Å for InGaSb and ±0.25 Å for InAs layers are required to retain optimization. Moreover, it is demonstrated that threshold current densities of the optimized superlattices do not obey a simple T o characteristic temperature parameterization due to sharp structure in the intersubband absorption spectrum, whereas nonoptimized structures have characteristic temperatures in the 30–65 K range. The microscopic calculations employ accurate K·p superlattice band structures and matrix elements, and evaluations of the gain, intersubband absorption, threshold carrier densities, and radiative and Auger recombination rates to obtain threshold current densities.