Mid-infrared interband cascade lasers based on type-II heterostructures

Interband cascade lasers take advantage of the broken-gap band alignment in type-II InAs/Ga(In)Sb heterostructures to reuse electrons for sequential p hoton emissions from successively connected active regions; thus, they repr esent a new type of mid-IR light source. The mid-IR interband cascade laser s have recently been demonstrated with large peak optical output powers (si milar to 0.5 W/facet), high differential external quantum efficiency (> 200 %), and near-room-temperature operation (286 K). Also, emission wavelength from interband cascade light-emitting diodes has been extended to as long a s 15 mu m; thus verifying the unique capability of this Sb-family type-II h eterostructure system to be tailored over a wide spectral range. In this wo rk, the explorations toward the demonstration and improvement of these inte rband cascade lasers will be reviewed. The features and issues related to t he design and modeling of the interband cascade lasers will also be discuss ed in connection with device performance. (C) 1999 Elsevier Science Ltd. Al l rights reserved.