Athermal optical waveguide apparatus and method of producing the same

摘要

An optical waveguide apparatus comprises a substrate (1), a core (4) patterned in a recessed portion of the substrate, and an upper cladding layer (10) formed on the substrate. The core is surrounded by a cladding comprising the substrate as a lower cladding layer and the upper cladding layer having both smaller refractive index than the core. The core and the cladding are integrally coupled to each other in a manner such that temperature-dependent expansion or contraction is performed substantially in accordance with the characteristic of the cladding. The core and the cladding are made of materials selected so that the variation in optical path length according to the temperature-dependent expansion or contraction of the cladding is cancelled by the variation in optical path length according to temperature-dependent variation in refractive index of the core.