Analysis of Threshold Current for InP/ AlGaInAs Multiple Quantum Well Ring Laser

Abstract

Due to the flexible functions and monolithic integration, semiconductor ring laser (SRL) has become a hot topic in the field of photonic and optoelectronic integration. In this paper, a new threshold current expression suitable for the circular SRL with multiple quantum well (MQW) material structure was derived from the oscillation condition of conventional Fabry-Perot cavity. The influences of ring radius, etching depth and waveguide separation on the threshold current were analyzed and numerically calculated. The calculation results indicated that the total loss of the circular SRL is mainly determined by the ring radius for small-size device. Compared with the shallow-etched devices, the deep-etched SRLs can lase even with smaller radius, and a minimum threshold current of 35mA was obtained for InP/ AlGaInAs MQW circular laser.