High-efficiency optical coupling to planar photodiode using metal reflector loaded waveguide grating coupler
For the realization of optoelectronic integrated circuits, it is required to incident light perpendicularly to a planar Si photodiode. We propose a high-efficient vertical optical coupler using an amorphous Si optical waveguide grating coupler with top reflector, which is transparent at 850nm wavelength range. The optical waveguide (width of 300nm \(\times \) height of 100nm) coupler is analyzed by using finite element method. The coupling efficiency of 80% is calculated at the grating period of 380nm, the duty ratio of 0.75 and the depth of 3565nm with top metal reflector.
grating coupler oeic silicon optical waveguide numerical simulation