Optical waveguide device

Abstract

An optical waveguide device includes a substrate on which an optical waveguide is formed, and an object that is disposed on the substrate. The optical waveguide includes a mode conversion/branching portion that converts a mode of a light wave propagating through the optical waveguide and branches the light wave, and the object is disposed to cover a part or the whole of the mode conversion/branching portion or not to cover the mode conversion/branching portion when the substrate is viewed in a plan view. In a case where the object is disposed to cover a part of the mode conversion/branching portion, the object is disposed not to consecutively cover a section over a length of a predetermined value or higher in an advancing direction of a light wave.

What is claimed is: 
     
         1 . An optical waveguide device comprising:
 a substrate on which an optical waveguide is formed; and   an object that is disposed on the substrate,   wherein the optical waveguide includes a portion that converts a mode of a light wave propagating through the optical waveguide and branches the light wave,   wherein the object is disposed to cover a part or the whole of the portion or not to cover the portion at all when the substrate is viewed in a plan view, and   wherein, in a case where the object is disposed to cover a part of the portion, the object is disposed not to consecutively cover a section over a length of a predetermined value or higher in an advancing direction of a light wave.   
     
     
         2 . The optical waveguide device according to  claim 1 ,
 wherein the predetermined value is 40 μm, and   wherein, in a case where the object is disposed to cover a plurality of discontinuous sections, a clearance of 20 μm or higher is provided between the sections.   
     
     
         3 . The optical waveguide device according to  claim 1 ,
 wherein the object is an electrode controlling a light wave propagating through the optical waveguide, or a reinforcing member reinforcing connection between an optical fiber through which a light wave is input to the optical waveguide and the substrate.   
     
     
         4 . The optical waveguide device according to  claim 1 ,
 wherein the substrate is a thin plate with a thickness of 20 μm or lower, and is reinforced with a reinforcing substrate adhered to the substrate.