| 摘要 |
PROBLEM TO BE SOLVED: To connect optical waveguides different in mode field diameter by reducing a connection loss owing to the uncoincidence of the mode field diameter without causing damage by heating to a substrate and the optical waveguide. SOLUTION: In connecting structure for the optical waveguide wherein the end surface of a second waveguide having the mode field diameter larger than the mode field diameter of a first optical waveguide is connected to the end surface of the first optical waveguide formed on the substrate by aligning optical axes of both optical waveguides, the mode field diameter of the first optical waveguide is brought close to the mode field diameter of the second optical waveguide by heating the vicinity of the end surface of the first optical waveguide and reducing the difference of refractive indexes between a core part 2 and a clad part 1 in the vicinity of the end surface. Thus, the connection loss owing to the uncoincidence of the mode field diameter in the connecting part is reduced, and since heating at a high temperature is not necessitated, damage to the substrate and the optical waveguide is reduced to an extent free from problems in practice. |
