Bandwidth-Enhancement of Silicon Grating Couplers Using Dispersive Coatings

The design of a highly efficient fiber-to-chip link using a silicon grating coupler with an enhanced optical bandwidth in a 250 nm silicon-on-insulator platform is presented. Consisting of a standard grating coupler with backside mirror and a special dispersive coating, this link offers a simple design and an enhanced 1-dB-bandwidth. Special attention is paid to the influence of the coating-dispersion on bandwidth. Optical simulations demonstrate the performance of the fiber-to-chip links at a wavelength of about 1550 nm and for the transverse electric waveguide mode.