Abstract: Planar optical waveguide apparatus and methods for fabricating planar optical waveguide apparatus. The apparatus has a core layer and a cladding layer, the core layer having at least one optical waveguide, and an alignment structure spaced from and positioned with respect to the at least one optical waveguide to facilitate measuring a position of the at least one optical waveguide. The alignment structure has a first alignment structure, such as a reflecting member, to facilitate measuring a height of the at least one optical waveguide; and a second alignment structure, such as alignment marks, to facilitate measuring positions of the at least one optical waveguide in a plane of the at least one optical waveguide. The method includes forming both the optical waveguide and at least a portion of the alignment structure simultaneously in a single processing step to ensure that the optical waveguide and the alignment structure are in perfect registration.