| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide in which a grating is easily formed not only in a core zone but also in a clad zone and which is usable as a high- performance narrow band wave selection filter. SOLUTION: In the optical waveguide 1 which is provided with a plane substrate 2, a core zone formed on the plane substrate 2, and clad zones 3 and 5 covering the core zone 4 and having a refractive index relatively smaller than that of the core zone 4, the core zone 4 is formed of a SiO2 glass containing GeO2 and the clad zones 3 and 5 are formed of a SiO2 glass containing SnO2 . |
