Inverse Design and Demonstration of Broadband Grating Couplers

We present a gradient-based optimization strategy to design broadband grating couplers. Using this method, we are able to reach, and often surpass,a user-specified target bandwidth during optimization. The designs produced for 220 nm silicon-on-insulator are capable of achieving 3 dB bandwidths exceeding 100 nm while maintaining central coupling efficiencies ranging from -3.0 to -5.4 dB, depending...