Patent ID: 7515793

Claim:
A waveguide photodetector comprising: a first silicon dioxide layer; a waveguide layer formed on a portion of the first silicon dioxide layer, where light is guided or is confined; and a detection layer formed on the waveguide layer, where guided light is detected, the detection layer functioning to guide the light and being formed of at least one of: single-crystal germanium, a silicon-germanium composite, or a silicon/germanium/carbon composite; a second silicon dioxide layer formed on the first silicon dioxide layer and positioned adjacent to a first longitudinal side of the waveguide layer and the detection layer; a third silicon dioxide layer formed on the first silicon dioxide layer and positioned adjacent to a second longitudinal side of the waveguide layer and the detection layer, such that the third silicon dioxide layer is separated from the second silicon dioxide layer by the waveguide layer and the detection layer; a first electrical contact coupled to the detection layer and positioned to straddle the second silicon dioxide layer and the detection layer; and a second electrical contact coupled to the detection layer and positioned to straddle the third silicon dioxide layer and the detection layer, wherein each of the waveguide layer and the detection layer allows for the guiding of no more than a single mode of light for a given polarization.