Direct intensity modulation of three-guide coupled rectangular ring laser having bidirectional lasing characteristics

Abstract

We investigate the modulation properties of a three-guide coupled rectangular ring laser having bidirectional lasing characteristics. Two different rectangular lasers having active section lengths of 250 and 350 μm and total cavity lengths of 580 and 780 μm are fabricated. The rectangular laser cavity consists of four low loss total internal reflection mirrors and an output coupler made out of three passive coupled waveguides. For both the clockwise and counterclockwise circulating directions, the lasing threshold currents of around 38 mA are obtained at room temperature under continuous wave operation. A 3-dB modulation bandwidth over 3 GHz is observed in both circulating directions for two different lasers.