US Patent 7480429 Chip to Chip optical interconnect

An apparatus for optical communication is provided. The apparatus includes a first waveguide formed on a first surface and a second waveguide formed on a second surface. The first and second surfaces are bonded together to form an air gap between the first and second surfaces and diffraction gratings of the first and second waveguides are facing each other. A third waveguide is formed on a third surface, and the third surface is bonded to the second surface so an air gap exists between the third and second surface and diffraction gratings of the third and second wave guides face each other. The light beam passes from the second wave guide across the air gap and into the third waveguide.