Patent ID: 7103252

Claim:
A multi-layer optical waveguide formed on a substrate comprising: a first core including a waveguiding part guiding light; a non-waveguiding part guiding no light, which includes two non-waveguiding sections, each arranged on opposite sides, respectively, of said waveguiding part; and portions of a cladding burying grooves defined by said waveguiding part and each of said two non-waveguiding sections and formed so as to have varying widths in a guiding direction, respectively, and other portions of the cladding formed on said waveguiding part having a varying thickness in the guiding direction corresponding to the widths of the grooves; a second core, formed on the cladding, comprising a waveguiding part guiding light, the waveguiding part of said second core including a portion thereof angled in a direction relative to the substrate corresponding to the thickness of the cladding formed on said waveguiding part of said first core, to thereby change a position of said waveguiding part of the second core in a layering direction.