Patent ID: 7161221

Claim:
A light receiving element for converting a light signal into an electric signal, comprising: a semiconductor substrate; a semiconductor layer; a photo-absorption layer interposed between the semiconductor substrate and the semiconductor layer; an active region having a window layer disposed at both ends and disposed on top of the photo-absorption layer, the semiconductor substrate comprises: a first groove having an inclination with respect to an incidence plane of the light signal so that the light signal can be refracted when the light signal has been incident on the first groove; a second groove for reflecting the light signal refracted by the first groove to be absorbed into the photo-absorption layer, so that a vertical-incidence drift of the light signal toward the photo-absorption layer is minimized; a first electrode formed at a first bottom of the semiconductor substrate; and a second electrode formed at a second bottom of the semiconductor substrate, wherein the light signal enters the semiconductor substrate at a substantially horizontal orientation, refracts upon entering the first groove at a predetermined angle and propagating towards the photo-absorption layer, and further refracted after being reflected by the second groove so that the light signal is propagating substantially perpendicular to the base of the semiconductor substrate.