Demonstration of a genetic-algorithm-optimized cavity-based waveguide crossing

A compact, single-etch silicon photonics waveguide crossing based on low quality factor cavity and optimized by a genetic algorithm is demonstrated. The device has 0.1~0.3 dB insertion loss and < -35 dB crosstalk per crossing for fundamental TE mode in the 1550-1600 nm wavelength band, with a footprint of 5 x 5 {\mu}m$^2$.