Fabrication of monolithic twin-GaInAs pin photodiode for balanced dual-detector optical coherent receivers

A monolithic twin-GaInAs/InP pin photodiode with planar, embedded structure has been fabricated for optical coherent receiver applications. High-uniformity (±1.5%) quantum efficiency and low capacitance (0.3 pF) have been achieved, and its advantage has been demonstrated by the intensity noise suppressions of a dual-detector balanced heterodyne receiver (better than −15 dB up to 4.2 GHz).