Mid-infrared interband cascade light emitting devices with milliwatt output powers at room temperature

We demonstrate incoherent light emission peaked at λ = 3.3 μm from a 15-stage interband cascade active region. The interband cascade light emitting devices with mesa diameters ranging from 50 to 400 μm were mounted epitaxial-side-down, and light was extracted from the substrate side. At an applied bias of 8.7 V and injection current of 0.6 A, and without any measures taken to improve the poor out-coupling efficiency caused by total internal reflection, a 400-μm-diameter device produced 1.6 mW of continuous-wave output power at T = 25 °C. Mesas with smaller diameters displayed emission intensities as high as 1.7 W/cm2.