Patent ID: 7138631

Claim:
A slab waveguide photodetector for detecting infrared radiation, the slab waveguide photodetector comprising: a first contact; an infrared absorbing layer for absorbing the infrared radiation, the infrared absorbing layer being in contact with the first contact, the first contact for making electrical contact to the infrared absorbing layer; a second contact for making electrical contact to the infrared absorbing layer, the second contact being in contact with the infrared absorbing layer, a signal being generated between the first and second contacts when the infrared absorbing layer absorbs the infrared radiation; a cladding layer for guiding the infrared radiation, the cladding layer exhibiting an index of refraction that is lower than an index of refraction of the second contact, the cladding layer being disposed on a surface of the second contact opposite the infrared absorbing layer; and a grating having a period suitable for launching the infrared radiation in a waveguide mode into the infrared absorbing layer, the grating being disposed on a surface of the cladding layer opposite the second contact, wherein a total thickness of the first and second contacts and the infrared absorbing layer is adapted to support the waveguide mode for the infrared radiation to be absorbed by the infrared absorbing layer.