Patent ID: 6868208

Claim:
A method of photoinducing a Bragg grating in an optical fiber ( 300 ) or a waveguide, in which a selected zone of the fiber ( 300 ) or waveguide is subjected to a step of being exposed with a source beam ( 120 ) using a mirror ( 200 ) in such a manner as to fold a portion ( 122 ) of the source beam ( 120 ) as reflected by the mirror ( 200 ) onto a portion ( 124 ) of the source beam that is not reflected by the mirror, thereby obtaining a diffraction grating in the fiber ( 300 ) or waveguide, the method being characterized in that an additional exposure step is performed on said portion of the fiber ( 300 ) or waveguide, and in that relative displacement is imparted between the two exposure steps to elements selected from the beam ( 120 ), the fiber ( 300 ) or waveguide, and the mirror ( 200 ), in such a manner as to cause a same portion of the beam ( 120 ) used for photoinduction in both exposure steps to be reflected by the mirror ( 200 ) in one of the steps and not reflected by the mirror ( 200 ) in the other step.