PHASE-ADJUSTING MASK FOR ARRAY WAVEGUIDE-TYPE DIFFRACTION GRATING AND MANUFACTURING METHOD OF ARRAY WAVEGUIDE-TYPE DIFFRATION GRATING BY USE OF THE MASK

摘要

PROBLEM TO BE SOLVED: To remove a phase shift between TE mode and TM mode. SOLUTION: In order to remove a deviation in phase of the array waveguide 15, an ultraviolet laser beam is radiated to ward each waveguide via each mask 19 and 21 of the masks 18 and 20, respectively, and the phase adjustment for each waveguide is made by the application of change in ultraviolet-ray induction refractive index. The length of each window 19 and 21 corresponds to the deviation in the phase of each waveguide. The optical modes (TE and TM) passing through the array waveguide 15 are inverted when they pass through the half-wavelength board 10. Accordingly, TE is different from TM in change in the refractive index induced by the radiation of the ultraviolet ray, but there is no deviation in phase between TE and TM as a whole.