Design of a Polarization-Insensitive and High-Efficiency Coplanar Edge Coupler for Silicon Photonics by Using a Polished Conical Silicon-Cored-Fiber

Optical coupling between an external optical fiber and a silicon waveguide is vital for successful silicon photonics applications. Direct edge coupling has been desirable but challenging in the past to substitute for bulky, non-coplanar grating-assisted coupling. A silicon-cored fiber (SCF) is proposed as a novel solution for coplanar light coupling from an incoming fiber to a silicon waveguide. The simulation results show that an optimized polished conical SCF coupler can reach very high coupling efficiencies in both TE and TM modes and with low polarization dependence.