MANUFACTURE OF OPTICAL WAVEGUIDE HAVING GRATING FORMED

摘要

PROBLEM TO BE SOLVED: To obtain the optical waveguide which has a grating capable of easily controlling refractive index modulation into an arbitrary shape by using only a part where the intensity distribution of ultraviolet light is uniform by moving the position irradiated with ultraviolet rays along a core and irradiating it with the ultraviolet rays. SOLUTION: A part where the clad layer of an optical fiber 1 is removed is fixed onto a stage 2 and a phase mask 3 is installed right above it. A mirror 6 reflects the ultraviolet light 4a emitted by a light source 7 on the optical fiber 1. The optical fiber 1 is irradiated only for a specific time with ultraviolet light 4b with a uniform intensity distribution cut out by a slit 5 through a phase mask 3 from above the phase mask 3. At the end of the irradiation, the mirror 6 is moved by a constant movement quantity P to move the position irradiated with the ultraviolet light 4b along the length of the optical fiber 1. The time of irradiation at each irradiation position is adjusted to form a grating having length L.