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.
Claims16
A method for writing a Bragg grating in a photosensitive waveguide portion, the method comprising:
- generating an ultraviolet radiation beam;
- providing a translation stage including a mirror and a screen, the screen including a slit along the beam path;
- deflecting said beam with the mirror and through the slit,
- displacing said translation stage parallel to said photosensitive waveguide portion to direct said deflected beam through a phase mask directly facing said photosensitive waveguide portion, and along a z axis of said photosensitive waveguide portion;
- and,
- changing the distance between said phase mask and said photosensitive waveguide portion during said displacing.
An apparatus for writing a Bragg grating in a waveguide, comprising:
- an emitter of an ultraviolet radiation beam;
- support elements of said waveguide for arranging a photosensitive waveguide portion in a writing position along a path of said beam;
- a phase mask arranged along said path in such a position as to directly face said photosensitive waveguide portion when the photosensitive waveguide portion is in writing position;
- means for scanning the beam along said photosensitive waveguide portion through said phase mask;
- a screen having a slit arranged along said path before said phase mask;
- a motorized translation stage carrying said screen and having an orthogonal displacement direction with respect to said beam for arranging said slit in different points of the section of said beam;
- and,
- a moving device for changing the distance between said phase mask and said photosensitive waveguide portion during the scanning of the beam.
Dependencies are inferred from the claim text.