Optical fiber with fresnel diffraction
First Claim
1. An optical fibre being optically transmissive at a predetermined wavelength of light λ
- and comprising a plurality of coaxial layers each having an optical path length that varies radially,an end-face; and
a lens portion that includes at least a portion of the coaxial layers;
wherein the coaxial layers are arranged to give the fibre a refractive index profile that causes sufficient Fresnel diffraction such that the light is guided in the fibre and diverted by the lens portion when passing out at the end-face.
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Accused Products
Abstract
An optical fiber being optically transmissive at a predetermined wavelength of light λ and comprising a plurality of coaxial layers. Each layer having an optical path length that varies radially, the coaxial layers being arranged to give the fiber a refractive index profile which, in use, causes sufficient Fresnel diffraction of the light such that it is guided in the fiber. The refractive index of a cladding region (60) is intermittently suppressed by controlling heating of the preform tube, thus forming a chirped saw-tooth profile (70). The optical fiber may include a lens. In this case, each of the layers has an optical path length that increases gradually outwardly by substantially n×λ/2 (n: integer).
7 Citations
31 Claims
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1. An optical fibre being optically transmissive at a predetermined wavelength of light λ
- and comprising a plurality of coaxial layers each having an optical path length that varies radially,
an end-face; and a lens portion that includes at least a portion of the coaxial layers; wherein the coaxial layers are arranged to give the fibre a refractive index profile that causes sufficient Fresnel diffraction such that the light is guided in the fibre and diverted by the lens portion when passing out at the end-face. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
- and comprising a plurality of coaxial layers each having an optical path length that varies radially,
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31. An optical fibre being optically transmissive at a predetermined wavelength of light λ
- and comprising a plurality of coaxial layers each having an optical path length that varies radially, the coaxial layers being arranged to give the fibre a refractive index profile which, in use, causes sufficient Fresnel diffraction of the light such that it is guided in the fibre;
wherein the optical fibre includes a lens and has an optical path length of each of the layers that increases gradually outwardly by substantially n×
λ
/2 (n;
integer), the layers being radially distributed, such that in use, the fibre effects sufficient Fresnel diffraction such that the light that is guided in the fibre and then passes out an end-face of the fibre, is focused substantially at a predetermined focal point.
- and comprising a plurality of coaxial layers each having an optical path length that varies radially, the coaxial layers being arranged to give the fibre a refractive index profile which, in use, causes sufficient Fresnel diffraction of the light such that it is guided in the fibre;
Specification