Patent ID: 8035181

Claim:
A semiconductor photodetector comprising: a semiconductor substrate having opposed first and second surfaces; a first multilayer reflective layer on the first surface of said semiconductor substrate and including a plurality of semiconductor layers; a first optically-resonant layer on said first multilayer reflective layer and having an optical thickness; a second multilayer reflective layer on said first optically-resonant layer and including a plurality of semiconductor layers; a light absorbing layer on said second multilayer reflective layer; a phase adjusting layer in physical contact with said light absorbing layer; a first electrode on said phase adjusting layer; and a second electrode and an antireflective film on the second surface of said semiconductor substrate and on which light detected by said photodetector is incident, wherein said first optically-resonant layer has a larger thickness than said semiconductor layers of said first and second multilayer reflective layers, and total optical thickness of the layers between said second multilayer reflective layer and said first electrode is not equal to the optical thickness of said first optically-resonant layer.