Sensitivity of optimization of mid-infrared InAs/InGaSb laser active regions to temperature and composition variations

We calculate the temperature dependence of the threshold current density J(th) in optimized (minimal J(th)) and unoptimized InAs/InGaSb superlattices. We find that the threshold current density of the unoptimized superlattice is well described by J(th)proportional to e(T/T0), with T-0 similar to 32 K from 25 to 275 It. This is the first microscopic calculation for these superlattices which indicates that J(th) is well described by an empirical exponential form. In contrast, the threshold current density of the optimized superlattice is not well parametrized by a characteristic temperature To. This superlattice is only optimized between 250 and 350 K, due to the sharp structure of the intersubband absorption spectrum, We also consider the effect on J(th) Of uncertainties in layer thicknesses, (C) 1998 American Institute of Physics.