OPTICAL INTERFEROMETER AND METHOD FOR WRITING PHASE STRUCTURES

摘要

A method of forming a grating structure (127) in a photosensitive waveguide (128) is disclosed comprising projecting a single beam of light (121) onto a phase mask (122) so as to create two coherent beams of light (123, 124); projecting the two coherent beams (123, 124) around an optical circuit (125, 126) so that they interfere at a first location; translating the phase mask (122) substantially perpendicular to the single beam of light (121); whilst simultaneously translating the photosensitive waveguide (128) substantially perpendicular to the single beam (121) so as to substantially minimize the variation in position of the intensity maxima of each fringe of the interference pattern in the reference frame of the waveguide (128) thus simultaneously writing a grating (127) along the portion of the waveguide within the interference pattern.