Interband cascade lasers with room temperature threshold current densities below 100 A/cm²

Interband Cascade Lasers (ICLs) with threshold current densities below 100 A/cm² in pulsed operation at room temperature are presented. The laser structure comprises 10 active stages of 41 nm length, each stage containing a W-quantum well active region for emission in the spectral region around 3.6 μm. A comparison of devices with 6 and 10 stages shows that the latter have a reduced threshold due to an increased optical confinement factor, very competitive threshold power densities of 428 W cm⁻² despite an increased threshold voltage and large differential slope efficiencies of 1390 mW/A. For a narrow ridge device, continuous wave operation is observed up to 65 °C.