Optical filter fabrication method using fiber holder with spiral groove and phase mask with spiral diffraction grating

摘要

An optical filter is manufactured by placing a photosensitive optical fiber in a spiral arrangement on a fiber holder, preferably having a spiral groove for holding the fiber, and exposing the fiber to ultraviolet light through a phase mask having a spiral diffraction grating, forming an in-fiber Bragg grating. The fiber can be conveniently scanned by an ultraviolet beam as the fiber holder and phase mask turn on a rotating stage. The fiber can be compactly packaged between the fiber holder and a cover. The fiber holder and cover can be formed by coating a substrate with layers of polymer material, the spiral groove being formed by photolithographic patterning of one of the layers.