| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical waveguide element serving as a spot size converter such that a decrease in coupling efficiency is suppressed even when the length of the spot size converter is made short.SOLUTION: There is provided an optical waveguide element comprising a first clad, a first optical waveguide core formed on the first clad while tapered toward a tip, a second optical waveguide core formed on the first clad while covering the first optical waveguide core, a second clad formed on the first clad while covering the second optical waveguide core, and a third clad formed on both sides of the second clad in a direction in which the first optical waveguide core and second optical waveguide core extend. The second optical waveguide core has a lower refractive index than the first optical waveguide core, the third clad has a lower refractive index than the second optical waveguide core, and the second clad has a lower refractive index than the third clad. |
