Patent ID: 7010207

Claim:
An optical waveguide device having a first cladding layer, a core formed on said first cladding layer for guiding light, and a second cladding layer formed on said first cladding layer and said core so as to surround said core, wherein: said core comprises a trunk portion constituting a body of said core, and a layered structure portion essentially perpendicular to a plane forming said first cladding layer; said trunk portion comprises a plurality of layers substantially horizontal to a plane forming said first cladding layer; adjacent layers in a plurality of layers forming said trunk portion are formed so as to differ in refractive index from each other; adjacent layers in a plurality of layers forming said trunk portion are formed such that refractive indices of said adjacent layers change stepwise; and a plurality of layers forming said trunk portion are formed such that a refractive index of a core layer of said core is made comparatively high and such that said refractive index is made smaller stepwise from said core section of said core toward an exterior layer and is again made larger.