Novel silicon-on-insulator grating couplers based on CMOS poly-silicon gate layer

Abstract

Grating couplers are widely investigated as a coupling interface between silicon-on-insulator waveguides and optical fibers. In this work, novel grating couplers based on strip poly-Si are proposed. This structure utilizes the poly-Si gate layer of the CMOS MOSFETs, and thus enables grating couplers integrated with CMOS circuits without adding any additional masks and process steps. Simulation results show that a coupling efficiency over 60% can be achieved between silicon-on-insulator waveguides and fibers.