High-temperature and low-threshold midinfrared interband cascade lasers

A broad-area midinfrared interband cascade (IC) laser has been demonstrated with a threshold current as low as similar to 630 A/cm(2) at 300 K. Despite exhibiting a large specific thermal resistance (similar to 56 K cm(2)/kW at 172 K), the device delivered cw power near 200 mW/facet at 500 mA and at 83 K and lased in cw mode up to 172 K. A 0.5-mm-long laser delivered cw power of similar to 253 mW/facet at 400 mA and at 82 K, and had power efficiency as high as 26% at similar to 80 K. Narrow mesa stripe IC lasers had relatively higher threshold current density, yet lased at temperatures up to 237 and 350 K in cw and pulsed modes, respectively. The feasibility of cw operation at higher temperatures and directions for improving IC laser performance are discussed based on the experimental data. (C) 2005 American Institute of Physics.