摘要：Using beam propagation method （BPM）, key optical design parameters of InP/AlGaInAs multiple quantumwell （MQW） ring laser were numerically analyzed. The influences of waveguide dimensions, curvature radiusand gap size on the coupling efficiency were discussed. An InP/AlGaInAs MQW ring laser with radius of 350 μm wasdesigned and realized. The experimental results show that the designed device, lasing at 1 563.2 nm with side modesuppression ratio higher than 20 dB, exhibited unidirectional bistability between the clockwise and counterclockwisemodes.