| 摘要 |
PROBLEM TO BE SOLVED: To prevent propagation of unwanted light by dispersedly arranging diffraction gratings so that the light radiated from any diffraction grating formed on a core to the outside of the core isn't made incident on other diffraction grating. SOLUTION: Plural cores 2 (2a, 2b) are arranged side by side upward a substrate of an optical waveguide 1. The diffraction gratings 4 (4a, 4b) reflecting only the light of a specified wavelength among propagation light propagating along the core 2 are formed on respective cores 2. The diffraction gratings 4 are formed by periodically changing e.g. the refractive indexes of the cores 2, and are provided with a function reflecting only the light of the wavelength according to the periods of the refractive indexes. Then, the diffraction gratings 4 are dispersedly arranged on respective cores 2, and even when the light is radiated from any one of diffraction gratings 4 to the outside of the cores 2, it is made so as not to be made incident on other diffraction grating 4. That is, it may be made so that other diffraction grating 4 isn't formed in the direction of a radiation angleθaround the position of the diffraction gratings 4 formed on the cores 2. |
