METHOD OF MANUFACTURING PHASE MASK FOR PROCESSING OF OPTICAL FIBER AND OPTICAL FIBER WITH BRAGG DIFFRACTION GRATING MANUFACTURED BY USING THAT PHASE MASK FOR PROCESSING OF OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide an method of manufacturing a phase mask for the processing an optical fiber to reduce connection errors which degrade the spectral waveform and the group delay characteristic of the optical fiber grating to be manufactured. SOLUTION: In the method of manufacturing a phase mask for the processing of an optical fiber, repeated patterns of recessed grooves and projected ridges like gratings are formed on one face of a transparent substrate to diffract light and the diffracted light is made to irradiate an optical fiber to form a diffraction grating in the optical fiber by the interference fringes of the diffracted light in different orders of diffraction. When a mask in which a plurality of patterns P1 to P5 with the pitches linearly or nonlinearly increased or decreased and the ratio of the width of the recessed groove to the projected ridge kept constant are arranged parallel to one another is to be manufactured, the mask is subjected to multiple exposure so as to decrease the deviation between the pitch in the connecting part between patterns having different pitch data and the pitch in each pattern.