Optical fiber grating and manufacturing method therefor

摘要

The present invention relates to an optical fiber grating manufacturing method comprising the steps of heating intermittently an optical fiber (4) provided with a core (1b) having residual stress in the longitudinal direction; softening a peripheral cladding (1c) of this core (1b); and forming spatial periodic changes for the relative refractive-index difference between said core (1b) and said cladding (1c), in the longitudinal direction of said fiber (4) by having the index of refraction of the core (1b) change through the releasing of said optical fiber. Next, as shown by a broken-line arrow, by the laser scanning device (6d), the laser beam (7) is scanned from the exterior side surface of the optical fiber (4), so as to be scanned traversing the optical fiber (4) in a direction perpendicular to the longitudinal direction of this optical fiber (4). At this time, the optical fiber (4) is heated to a temperature at least equal to or higher than the softening temperature of the cladding (1c).