Patent ID: 7599585

Claim:
An optical apparatus, comprising: a semiconductor substrate; a semiconductor optical device integrally formed on the substrate and having an etched device end face; and a low-index planar optical waveguide integrally formed on the semiconductor substrate at the etched device end face and end-coupled at its proximal end to the optical device through the etched device end face, the integrally-formed waveguide being arranged so as to comprise a waveguide mode converter, the integrally-formed waveguide being arranged at its distal end to transmit or receive an optical signal through its distal end to or from a discrete low-index optical waveguide end-coupled with the integrally-formed waveguide and assembled with the integrally-formed waveguide, with the optical device, or with the substrate, wherein: the semiconductor substrate, the semiconductor optical device, and the low-index planar optical waveguide together form a single monolithically integrated optical structure; the etched device end face includes an outwardly protruding portion extending along the substrate from a bottom portion of the device end face beneath a proximal portion of the integrally-formed end-coupled waveguide; and at least one layer of the end-coupled waveguide decreases in thickness toward the etched device end face, the outwardly protruding portion of the etched device end face and the decreasing layer thickness together yielding a desired layer surface profile for at least one layer of the integrally-formed end-coupled waveguide.