| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide having a new structure and a small optical loss which depends on the roughness of the side face of a core layer despite that the relative refractive index differenceΔbetween the core layer and a clad layer is large and to provide a method for manufacturing the optical waveguide. SOLUTION: The optical waveguide has the core layer 3 of which the refractive index is nb and the clad layer 2 which is provided outside the core layer 3, the refractive index nc of the clad layer is smaller than that of the core layer 3, and a high refractive index region 4, of which the refractive index is na (na>nb), is formed in the core layer by irradiating the inside of the core layer 3 with an ultra-short pulse laser beam of which the pulse width is 1000 femtosecond or smaller and the beam spot diameter is converged into a prescribed value. |
