REDUCED THRESHOLD ALL-OPTICAL BISTABILITY IN ETCHED QUANTUM-WELL MICRORESONATORS

All-optical bistability is demonstrated in GaAs/AlGaAs multiple quantu m well microresonators fabricated by SiCl4 reactive ion etching. A fab rication process has been developed in order to obtain low threshold b istability. The studied samples are two-dimensional 15X15 arrays of cy lindrical microresonators of 4 mu m diam and 6 mu m height. Owing to l ateral carrier and light confinement, bistability is observed with a s trongly reduced threshold power, below 100 mu W. This result-was obtai ned without post-etching surface treatment. The low bistability thresh old suggests that the surface recombination rate is reasonably small, possibly due to some self-passivation occurring during the etching pro cess.