Multimode interference-based two-stage 1 * 2 light splitter for compact photonic integrated circuits

A novel two-stage multimode interference 1 * 2 light splitter is proposed and fabricated in indium phosphide. The new splitter design is shorter by as much as 50% than a standard multimode-interference light splitter with the same output waveguide spacing. It has low inherent loss of 0.29 dB, low excess loss of 1.5 dB over 80-nm range, and imbalance of less than 0.25 dB over 100 nm.