Asymmetric multiple-quantum-well heterostructures: band-gap engineering conception of optoelectronic elements with widened functionality

Approach of asymmetric multiple-quantum-well heterostructures is one of the basic conceptions in development of solid-state photomultipliers, infrared photodetectors, optical modulators, polarization insensitive light amplifiers, different type coherent sources, including tunable and bistable laser diodes, quantum cascade lasers, and other optoelectronic devices. In the paper, main attention is devoted to the obtained results in the study of dynamic and spectral characteristics of the quantum-well heterostructure lasers with active regions of different widths and compositions. Due to the asymmetric quantum-well heterostructures new possibilities to control spectral, power, and temporal properties of laser diodes and to widen their functionality are opened up. Recent results in the making of quantum cascade lasers, broad-band transmitters, quantum-well infrared photodetectors, and other optoelectronic elements are also mentioned.