MINIMIZATION OF PHASE ERRORS IN LONG-FIBER BRAGG GRATING PHASE MASKS MADE USING ELECTRON-BEAM LITHOGRAPHY

Centimeter-long fiber Bragg grating phase masks having several thousan d periods are fabricated using electron beam lithography and require t he stitching together of many electron beam writing fields. Two techni ques are used to minimize the effect of phase errors arising from the stitching profess, Fiber Bragg gratings with more than 99.9% reflectiv ity are photoimprinted using the phase masks and near perfect spectral response is obtained in spite of stitching errors.