Optical waveguide device and fabricating method thereof

Optical waveguide device has waveguide strip-shaped in the depth direction of the drawing and protruding from peripheral portion. A core (not illustrated) is disposed inside waveguide. Wall to be cut is integrated with waveguide to form one core layer. No unevenness occurs in a cutting line of wall indicated with broken line. Accordingly, high-precision cutting is enabled by cutting wall along the cutting line.