Ultra-broadband Four-mode Waveguide Crossing via Inverse Design Method

An ultra-broadband four-mode waveguide crossing with a footprint of only 7.8 × 7.8 μm
²
is designed on silicon photonic platform. The insertion loss of the device is less than 0.73 dB, and the crosstalk is below -30 dB for 1400-1800 nm.