Optical waveguide device

An optical waveguide device comprising:

• a first cladding layer;
• a core layer disposed on the first cladding layer and forming a plurality of cores;
• and
• a second cladding layer disposed on the first cladding layer and selectively covering the core layer,
• wherein a first region not covered by the second cladding layer is provided on the first cladding layer,
• wherein the plurality of cores include:
• a plurality of signal cores, a first end of which is disposed in the first region, for inputting or outputting signal light;
• and
• an inspection core, a first end and a second end of which are exposed at an outer perimeter surface of the optical waveguide device, for inputting or outputting inspection light, and
• wherein the inspection core is made of a same material as the signal cores, and
• a cross-sectional shape of the inspection core in a short-hand direction thereof is identical to a cross-sectional shape of each of the signal cores in a short-hand direction thereof.