GRATING WRITING METHOD AND APPARATUS

摘要

A method of forming a grating structure on a photosensitive waveguide (2) is disclosed, the method including the steps of: moving the photosensitive waveguide (2) at a first substantially constant velocity perpendicular to a shuttered beam of light (12) in the photosensitive range; and emitting a shuttered beam at the photosensitive waveguide at predetermined times so as to form the grating structure within the beam. The shuttered beam of light can form an interference pattern (16) on the photosensitive waveguide and the shuttered beam can be operated so as to strobe the interference pattern such that subsequent strobes are substantially aligned on the waveguide so as to form a grating thereon. The interference pattern can be formed from two coherent beams (13, 14) projected around a Sagnac loop. Alternately, the shuttered beam can be focussed on the photosensitive waveguide to a point less than substantially 1500 nanometers.