METHOD AND DEVICE FOR MANUFACTURING OPTICAL WAVEGUIDE TYPE DIFFRACTION GRATING ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a method for easily manufacturing an optical waveguide type diffraction grating element even when the amplitude distribution of refractive-index modulation is not constant. SOLUTION: The refractive-index change induction light UV emitted by a light source 321 after passing through a shutter 322 and an optical system 323 is reflected by a mirror 324 to pass through a phase grating mask 200 and an optical fiber 110 is irradiated with the resultant light UV. Through the diffraction of the phase grating mask 200, +1st-order diffracted light and -1st-order diffracted light are generated and interfere with each other to form interference fringes having a fringe interval A. The mirror 324 moves along a z axis, and thus the irradiated position of the optical fiber 110 with refractive- index change induction light UV through the phase grating mask 200 is scanned. When the mirror 324 moves and the optical fiber is irradiated with the refractive-index change induction light UV, the phase grating mask 200 vibrates along the z axis through the operation of a piezoelectric element 330.