To provide a method for manufacturing a fiber grating by irradiation with UV laser light while imparting apodization to the fiber grating.
The method is carried out by use of a two-beam interference device that symmetrically splits UV laser light into two beams using a phase mask, reflects the beams by mirrors symmetrically disposed, and allows the beams to intersect and interference at the position of an optical fiber. First, a first fiber grating is formed, and consecutively the two mirrors are symmetrically rotated at a minute angle to form a second fiber grating as superposing on the first grating, wherein the fiber grating is formed by controlling the mirror rotation angle in such a manner that the phase in the longitudinal direction of the refractive index modulation by the two fiber gratins is identical at the center of the fiber grating and is shifted by 180° shift at the ends.
MIZUTANI YASUO
YAMAUCHI MAKOTO
IZUMIKAWA EIJI
KIMURA MASANORI
KAGAWA PREFECTURE