Optical bistability in injection laser diodes

Optical bistability in injection laser diodes is reviewed with special emphasis on the need for lower power requirements, improved contrast ratios, and higher speeds if devices are to find applications in optical signal processing and optical memories. Recent forms of bistability suggest that the need for spatial redistribution of charge carriers can be much reduced compared to that in conventional absorptive or dispersive bistable devices. If dependence on the relatively slow recombination processes which help to spatially redistribute electrons can be removed, then there is promise for greatly improved switching speeds. Quantum well materials appear to be most promising for many of these future advances.