PROCESS FOR WRITING BRAGG GRATINGS, APPARATUS FOR THE USE OF THIS PROCESS AND BRAGG GRATING DEVICES OBTAINED BY THIS PROCESS

摘要

The invention concerns a method for forming a Bragg grating in an optical waveguide (36) which consists in directly transferring into the substrate, by a photosensitivity phenomenon within said substrate itself, the interference figure between two light beams (28, 30) offset at an angle, of same wavelength and coherent, said interference figure being transferred, in the substrate, in the form of a modulation of the substrate refractive index. At least one of the beams is divided with a phase plate (42) into at least into two sub-beams with phase displacement with respect to each other.