Method and apparatus for writing a bragg grating in a waveguide
AssigneeCorning Incorporated
InventorMaurizio Tormen
Life of this patent
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Abstract
In order to create a diffraction grating in an optical fiber with a predetermined pattern of the refractive index, an ultraviolet radiation beam (3) is scanned (5, 8) along a phosensitive portion (F′) of the fiber through a phase mask (9) and, during the scan, the beam intensity (4) and the mask-fiber distance (10) are controlled moment by moment in such a way as to obtain the desired patterns of the mean value and of the envelope of the refractive index, respectively.
Claims20
Method for writing a Bragg grating in a waveguide, comprising the steps of:
- providing a photosensitive waveguide portion in a writing position;
- generating an ultraviolet radiation beam;
- and
- scanning said beam along a z axis of said photosensitive waveguide portion through a phase mask directly facing said photosensitive waveguide portion;
- characterised in that, during said scan, the step of changing the distance between phase mask and photosensitive waveguide portion is carried out.
Method according to any one of the previous claims, characterised in that said step of scanning said beam comprises translating said photosensitive waveguide portion along said z axis.
Method according to any one of the previous claims, characterised in that it comprises the step of focusing said beam on said portion of photosensitive waveguide.
Apparatus (1;
- 1′) for writing a Bragg grating in a waveguide (F), comprising:
- an emitter (2) of an ultraviolet radiation beam (3);
- support elements (13) of said waveguide (F) for arranging a photosensitive waveguide portion (F′) in a writing position along a path of said beam (3);
- a phase mask (9) arranged along said path in such a position as to directly face said photosensitive waveguide portion (F′) when the latter is in writing position;
- and
- means (5-8;
- 6-8) for scanning the beam (3) along said photosensitive waveguide portion (F′) through said phase mask (9);
- characterised in that it comprises a moving device (10) for changing the distance between said phase mask (9) and said photosensitive waveguide portion (F′) during the scan of the beam.
Dependencies are inferred from the claim text.