| 摘要 |
PROBLEM TO BE SOLVED: To prevent adhesion of organic decomposition products, dusts or the like on a grating face of a phase grating used in forming a diffraction grating in an optical fiber or a plane optical waveguide. SOLUTION: In a manufacturing method of such an optical fiber with a diffraction grating that the diffraction grating is formed in a part in the longitudinal direction of the optical fiber 1, the optical fiber 1 including a photosensitive dopant in the core is placed linearly, and a phase grating 2 is arranged in parallel therewith, and an ultraviolet-ray transmission glass board 3 is arranged between the phase grating 2 and the optical fiber 1, in parallel with the phase grating 2 and the optical fiber 1. Then, an ultraviolet ray 4a is irradiated to the phase grating 2 from the side, where the optical fiber 1 is not arranged, of the phase grating 2, and by interference light of the ultraviolet ray 4a passing through the phase grating 2 and the ultraviolet-ray transmission glass board 3, a refractive index of the photosensitive dopant included in the core of the optical fiber 1 is changed to form a diffraction grating in the optical fiber 1. In the case of this plane optical waveguide, the plane optical waveguide is arranged on the position of the optical fiber 1, so that the face thereof becomes parallel to the diffraction grating 2, and the diffraction grating 2 is formed on a straight line part of the core. |
