Patent ID: 8693820

Claim:
An optical waveguide, comprising: a substrate; an upper clad layer arranged on the substrate; and an optical waveguide structure, disposed in the upper clad layer so as to be parallel to a surface of the substrate, and including a flat optical waveguide having a first edge face and a second edge face at respective opposite sides thereof, channel optical waveguides each connected with said first edge face and extending radially therefrom, the channel optical waveguides each having lateral sides perpendicular to said substrate surface, the lateral sides of each channel optical waveguide being spaced apart from each other by a distance that increases with increasing distance from the first edge face, and an input optical waveguide connected with the second edge face, wherein the value of an integral of an optical intensity measured at bonding faces that bond the flat optical waveguide and the channel optical waveguides is the same to a value of an integral of an optical intensity measured at clearance gaps that are disposed at the first edge face and between the channel optical waveguides and the first edge face.