Low threshold 3 μm interband cascade “W” laser

Abstract

We have demonstrated the operation at λ ≈ 3.0 μm of a 22-stage interband cascade laser with a “W” active region for enhanced gain. The threshold current density for a ridge structure is 170 A/cm2 at 80K, and it remains lower than the best reported intersubband quantum cascade laser results at all T up to the maximum lasing temperature of 225K. At T = 100K, peak output powers up to 532 mW are observed, and the slope of 342 m W/A per facet for high injection levels corresponds to a differential quantum efficiency of 1.6 photons emitted for every injected electron.