| 摘要 |
PROBLEM TO BE SOLVED: To reduce loss in an optical waveguide circuit, and to further miniaturize and integrate a device. SOLUTION: The optical waveguide circuit is equipped with a plurality of 1st cores 203 whose space between each other is widened according as they go away from the branching point or the joining point of an optical signal, a clad 205 in which at least the 1st cores are embedded, and a 2nd core 204 provided between the 1st core and the clad, covering over at least one part of the 1st core and also formed in a gap between the 1st cores near the branching point or the joining point. The refractive index of the 2nd core is larger than that of the clad, a boundary between the 2nd core and the clad is smooth, and the film thickness of the 2nd core formed in the gap between the 1st cores is made thinner according as the space between a plurality of 1st cores is widened. COPYRIGHT: (C)2004,JPO |
