Fabrication of optical waveguide gratings
AssigneePirelli Cavi e Sistemi S.p.A.
InventorsRichard Ian Laming, Morten Ibsen
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Abstract
An optical grating fabrication apparatus having a phase mask for dividing an incident light beam into a plurality of diffracted beams and a focusing arrangement for receiving light from the phase mask and converging at least two non-zero-order diffracted beams together so as to generate an interference region of a characteristic period between the converged beams so that a grating structure can be impressed on an optical waveguide placed in the interference region. Further, a translation stage is arranged to move the phase mask and at least a part of the focusing arrangement with respect to one another under control of a control circuit so as to alter the angle of convergence of the converged beams and thus controllably tune the characteristic period.
Claims10
Optical grating fabrication apparatus comprising:
- a phase mask for dividing an incident light beam into a plurality of diffracted beams;
- a focusing arrangement having an optical axis extending approximately perpendicular to the phase mask so as to receive light from the phase mask and converge at least two non-zero-order diffracted beams together so as to generate an interference region of a characteristic period between the converged beams so that a grating structure can be impressed on an optical waveguide placed in the interference region;
- and
- a translation stage arranged to move at least one of the phase mask and at least a part of the focusing arrangement so as to alter their relative separation along the optical axis under control of a control circuit and thereby alter the angle of convergence of the converged beams and thus controllably tune the characteristic period.
An optical grating fabrication method comprising the steps of:
- directing a light beam onto a phase mask to divide the light beam into a plurality of diffracted beams;
- converging at least two non-zero-order diffracted beams together using a focusing arrangement having an optical axis extending approximately perpendicular to the phase mask so as to generate an interference region of a characteristic period between the converged beams so that a grating structure can be impressed on an optical waveguide placed in the interference regions;
- and
- causing relative movement between the phase mask and at least a part of the focusing arrangement to alter their relative separation along the optical axis so as to alter the angle of convergence of the converged beams and tune the characteristic period to a desired period.
Dependencies are inferred from the claim text.