The optical coupler consists of three parallel dielectric waveguides. The propagation constants of each waveguide are slightly mismatched so that coupling among them is weak. Two adjacent waveguides are passive ridge guides, and the third is an active waveguide.
Yijing ChenSeng Tiong HoVivek Krishnamurthy
T. R. LinQingyuan MiaoJian HeCaiyun LiPingan He