Inapplicability Of A Simply Parameterized Threshold Current In Sb-Based Ir Lasers

We examine theoretically the influence of temperature and composition on the threshold current densities of mid-wave infrared lasers with active regions consisting of InAs/InGaSb superlattices. Temperature shifts of the bands may result in significant variations in intersubband absorption and Auger recombination rates, giving rise to a threshold current density that is not well parameterized by a characteristic temperature To. Superlattices that are optimized to have minimal threshold current densities are shown to require +/- 3.5 Angstrom accuracy in InGaSb layer thicknesses, and +/- 0.25 Angstrom accuracy in InAs layer thickness in order to retain optimum operating characteristics.