All-Optical Response of Semiconductor Ring Laser to Dual-Optical Injections

The all-optical response of a semiconductor ring laser (SRL) to two optical injections is characterized. Once the lasing direction is locked by one optical injection, the SRL direction of operation can be switched by another optical injection into the counterpropagating direction. The switching process manifests a typical bistable hysteresis loop, with its width and switching thresholds variable by the first injection power. Extremely sharp transition has been measured which confirms the potential of the SRL for all-optical regeneration applications.