Advances in the growth and performance of antimonide-based mid-infrared interband cascade lasers

We discuss the growth and state-of-the-art performance characteristics of mid-infrared interband cascade lasers. Broad-area devices with 5 active stages display pulsed threshold current densities as low as 400 A/cm² at room temperature, owing to an unexpectedly strong suppression of Auger recombination. New designs also produce lasers with internal losses as low as ≈ 6 cm^-1 at room temperature. We also study the performance of narrow ridges that dissipate heat efficiently for high-temperature cw operation. The degradations of the threshold current density and differential slope efficiency are modest until the ridge width is decreased to 3 μm. A 13-μm-wide uncoated ridge produces up to 45 mW of cw power at 293 K, and displays a maximum wall-plug efficiency of 3.5%. A 5-μm-wide 3-mm-long ridge without any facet coatings operates cw to 345 K, which is a new record high temperature for any semiconductor laser emitting in the 3.0-4.6 μm spectral range.