Bragg gratings in waveguides
AssigneeNorthern Telecom Limited
InventorKevin Christopher Byron
Life of this patent
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Abstract
A method of generating a Bragg reflective grating in a photosensitive optical waveguide using a fringe pattern of electromagnetic radiation additionally employs a further beam of radiation to promote differential heating of the fibre in the region where the grating is being generated. The differential heating produces differential photo-sensitivity of the fibre so that the resulting grating, though it has a constant physical pitch, has an effective optical pitch that is a function of position along the length of the grating.
Claims5
A method of creating, in a length of photosensitive optical waveguide, a Bragg reflection grating by lateral illumination of the waveguide with a fringe pattern of electromagnetic radiation, wherein, concurrently with at least a portion of said lateral illumination of the waveguide with a fringe pattern to create therein a Bragg reflection grating, the length of the waveguide in which the grating is being created is differentially heated by radiation providing a heat flux that is functionally dependent upon position along the length of the grating.
A method of creating, in a length of photosensitive optical waveguide, a Bragg reflection grating by lateral illumination of the waveguide with a fringe pattern of electromagnetic radiation, in the course of which grating creation the length of the waveguide in which the grating is being created is differentially heated by radiation providing a heat flux that is functionally dependent upon position along the length of the grating, wherein the differential heating is provided by a focused beam of radiation traversed along the length of the grating, and wherein the optical power of the focused beam is varied during the traversal.
A method of creating, in a length of photosensitive optical waveguide, a Bragg reflection grating by lateral illumination of the waveguide with a fringe pattern of electromagnetic radiation, in the course of which grating creation the length of the waveguide in which the grating is being created is differentially heated by radiation providing a heat flux that is functionally dependent upon position along the length of the grating, wherein the differential heating is provided by a focused beam of radiation traversed along the length of the grating, and wherein during the traversal an additional heating source is employed to flood the grating with heating radiation.
Dependencies are inferred from the claim text.