DIRECTIONAL COUPLER AND ITS PRODUCTION

摘要

PURPOSE:To provide the directional coupler which can integrate devices at a large scale and has stable optical coupling characteristics and the process for production thereof. CONSTITUTION:The optical coupling region of a lower optical waveguide layer 2 is removed. A clad layer 3a lifted in a perpendicular direction while exposing the removed end face of the lower optical waveguide layer 2 is formed in this removed region. An optical waveguide coupling layer 2a coupling the exposed and removed end face of the lower optical waveguide layer 2 is formed on the clad layer 3a lifted in the perpendicular direction. A second clad layer 7 is formed at a prescribed thickness on the coupled lower optical waveguide layer 2. An upper optical waveguide layer 8 optically coupling to the optical waveguide coupling layer 2a is formed on this second clad layer 7. Finally, a third clad layer 9 is formed.