Novel optical bistability and hysteresis in multiple-quantum-well lasers

Summary form only given, as follows. Bistable semiconductor lasers have potential applications in future optical communication, optical switching, optical computing. Although gain saturation alone could account for the bistability, the inclusion of absorption saturation could make the bistability easier to occur. As a result, multi-electrode semiconductor lasers are usually used for optical bistability. We report that bistability exists in the semiconductor lasers without multiple sections. Using multiple quantum wells of different widths, both gain quenching and saturable absorption could occur in the same region for bistability. The semiconductor lasers that exhibit optical bistability have four quantum wells with their widths 20 /spl Aring/, 33 /spl Aring/, 56 /spl Aring/, and 125 /spl Aring/ respectively, separated by 150 /spl Aring/ Al/sub 0.2/Ga/sub 0.8/As barrier. An external-cavity configuration with broadband tunability was used for the bistability experiment. Different behaviors of bistability had been discovered for different wavelengths and the L-I curve with obvious bistability id presented. The details of experiments are discussed.