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 photon emissions from successively connected active regions; thus, they represent a new type of mid-IR light source. The mid-IR interband cascade lasers have recently been demonstrated with large peak optical output powers (similar 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 as 15 mu m; thus verifying the unique capability of this Sb-family type-II heterostructure system to be tailored over a wide spectral range. In this work, the explorations toward the demonstration and improvement of these interband cascade lasers will be reviewed. The features and issues related to the design and modeling of the interband cascade lasers will also be discussed in connection with device performance. (C) 1999 Elsevier Science Ltd. All rights reserved.