High-efficient InP-based balanced photodiodes integrated with 90° hybrid MMI for compact 100 Gb/s coherent receiver

InP-based balanced photodiodes monolithically integrated with the 90° hybrid consisting of multimode interference structures (MMI) by the butt-joint process were demonstrated for the first time. The high responsivity of 0.14 A/W and wide 3-dB bandwidth of 22 GHz at a low reverse bias voltage of 1.6 V were successfully achieved.