| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing optical waveguide diffraction grating element, and the like, capable of easily manufacturing an optical waveguide diffraction grating element even if the amplitude distribution of refractive index modulation is not constant. SOLUTION: A refractive index change inducing light UV outputted from a light source 321 is projected to an optical fiber 110 through a phase lattice mask 200. Two conditions (first condition and second condition) are set for relative positional relationship between the optical fiber 110 and the phase lattice mask 200. In the second condition, compared with the first condition, the phase lattice mask 200 is arranged to be relatively shifted in (z) direction by a half-cycle (Λ/2) of the diffraction grating, which is caused by refractive index modulation. In the first condition, the irradiation position of the refractive index change inducing light UV is scanned in the (z) direction across the refractive index modulation forming range with a first irradiation time distribution T1 (z). In the second condition, the irradiation position of the refractive index change inducing light UV is scanned in the (z) direction across the refractive index modulation forming range with a second irradiation time distribution T2 (z). |
