A High-Efficiency Grating Coupler on 220-nm SOI Platform with a Minimum Feature Size of 130nm

An inverse-designed dual-etched grating coupler optimized by the adjoint method is numerically demonstrated on a standard 220-nm silicon-on-insulator platform with a minimum feature size of 130nm. The coupling efficiency reaches 79.7% (−0.99dB), rendering it promising for low-cost and large-scale manufacturing by deep ultraviolet lithography.