HIGH-POWER MIDINFRARED INTERBAND CASCADE LASERS BASED ON TYPE-II QUANTUM-WELLS

We report a high power mid-infrared interband cascade laser operating at temperatures up to 170 K. The threshold current densities of this l aser are considerably lower than the previously reported values in cas cade lasers. The structure was grown by molecular beam epitaxy on a Ga Sb substrate and comprises 23 periods of active regions separated by d igitally graded multilayer injection regions. A peak optical output po wer of similar to 0.5 W/facet and a slope of 211 mW/A per facet, corre sponding to a differential external quantum efficiency of 131%, are ob served at 80 K and at a wavelength of similar to 3.9 mu m. (C) 1997 Am erican Institute of Physics. [S0003-6951 (97)00443-9].