A monolithic phase measurement photodetector

A novel monolithically integrated photodetector used as an optical phase-shift sensor is presented It consists of a diffraction grating etched at the surface of a p-n photodiode fabricated by standard silicon CMOS technology. This device provides the phase relationship between two coherent light beams collimated toward the surface of the photodetector. The operating principle of this sensor is presented along with the first devices fabricated and the experimental validation of the concept is demonstrated by performance characterization.