Dispersion manipulating fibre
First Claim
1. A micro-structured optical fibre for transmitting at least a predetermined wavelength of light, said optical fibre having an axial direction and a cross section perpendicular to said axial direction, said optical fibre comprising:
- a core region having a multiplicity of spaced apart core features that are elongated in the fibre axial direction and disposed in a core material, said core region having an effective index of refraction Nco, a cladding region surrounding said core region, said cladding region comprising a multiplicity of spaced apart cladding features that are elongated in the fibre axial direction and disposed in a first cladding material, and said cladding region having an effective index of refraction Ncl, wherein a plurality of said cladding features have a cross-sectional dimension perpendicular to said axial direction being larger than said predetermined wavelength.
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Accused Products
Abstract
Micro-structured optical fibers are improved with respect to increasing the dispersion, both to large negative or large positive values, in a first fiber design in which the fiber has a micro-structured core region being surrounded by a micro-structured cladding region with cladding features being large compared to a predetermined wavelength of light, which can be guided through the fiber. Preferably, the effective index of refraction of the core region, Nco, is larger than the effective index of refraction of the cladding region, Ncl, at the predetermined wavelength of light. It is further preferred that the refractive index of one or more of the core features is lower than the refractive index of the core material. Increased dispersion is also obtained by a second optical fiber design in which the fiber has two cladding regions, where the inner cladding region may be micro-structured with inner cladding features and having an effective refractive index that is larger than the effective refractive index of the outer cladding region at the operating wavelengths, i.e. the fiber has an inner cladding with a raised effective refractive index. For the second fiber design it is preferred that the outer cladding region is micro-structured with outer cladding features. There is further provided a third optical fiber design, which may be used for non-linear applications, and in which the use of a raised, inner cladding provides the flexibility to obtain fibers with very, small cores and near-zero dispersion over a broad wavelengths range at near-infrared wavelengths. In the third fiber design, the optical fiber has a core region surrounded by an inner cladding region with a number of inner cladding features disposed in an inner cladding material, while the inner cladding region is surrounded by an outer cladding region. In the third design the inner cladding features have a refractive index that differs from the refractive index of the inner cladding material, and the inner cladding region has an effective refractive index Ni that is larger than the effective refractive index No of the outer cladding region at the operating wavelength. The core region of the third design may be a substantially solid core with an effective refractive index Nco being larger than Ni at the operating wavelength. For the third design, the outer cladding region may also comprise a number of outer cladding features disposed in an outer cladding material, with the outer cladding features having a refractive index that differs from the refractive index of the outer cladding material. For the third fiber design it is preferred that the effective refractive index difference between the core region and the inner cladding region is greater than about 5%.
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Citations
171 Claims
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1. A micro-structured optical fibre for transmitting at least a predetermined wavelength of light, said optical fibre having an axial direction and a cross section perpendicular to said axial direction, said optical fibre comprising:
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a core region having a multiplicity of spaced apart core features that are elongated in the fibre axial direction and disposed in a core material, said core region having an effective index of refraction Nco, a cladding region surrounding said core region, said cladding region comprising a multiplicity of spaced apart cladding features that are elongated in the fibre axial direction and disposed in a first cladding material, and said cladding region having an effective index of refraction Ncl, wherein a plurality of said cladding features have a cross-sectional dimension perpendicular to said axial direction being larger than said predetermined wavelength. - 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, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 127, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171)
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66. An article comprising a micro-structured optical fibre for guiding light at an operating wavelength, said optical fibre having an axial direction and a cross section perpendicular to said axial direction, the optical fibre comprising:
- a core region having en effective refractive index Nco and being surrounded by a cladding region comprising a multiplicity of spaced apart cladding features being elongated in the axial direction and disposed in a first cladding material, the cladding features having a refractive index that differs from a refractive index of the first cladding material, the cladding region further comprising an inner cladding region surrounding the core region and an outer cladding region surrounding the inner cladding region, the inner cladding region having an effective refractive index Ni and the outer cladding region having an effective refractive index No, with Ni being larger than No at the operating wavelength.
- View Dependent Claims (67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 128, 129, 130, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160)
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69. An article comprising a micro-structured optical fibre for guiding light at an operating wavelength, said optical fibre having an axial direction and a cross section perpendicular to said axial direction, the optical fibre comprising a core region surrounded by an inner cladding region that comprises a multiplicity of spaced apart inner cladding features that are elongated in the axial direction and disposed in an inner cladding material, the inner cladding region being surrounded by an outer cladding region that comprises a multiplicity of spaced apart outer cladding features that are elongated in the axial direction and disposed in an outer material, the inner cladding features having a refractive index that differs from a refractive index of the inner cladding material and the inner cladding region having an effective refractive index Ni, and the outer cladding features having a refractive index that differs from a refractive index of the outer cladding material and the outer cladding region having an effective refractive index No, wherein Ni is larger than No at the operating wavelength.
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131. An article comprising a micro-structured optical fibre for guiding light at an operating wavelength, said optical fibre having an axial direction and a cross section perpendicular to said axial direction, the optical fibre comprising a core region having an effective refractive index Nco and being surrounded by an inner cladding region that comprises a multiplicity of spaced apart inner cladding features that are elongated in the axial direction and disposed in an inner cladding material, the inner cladding region being surrounded by an outer cladding region that comprises a multiplicity of spaced apart outer cladding features that are elongated in the axial direction and disposed in an outer material, the inner cladding features having a refractive index that differs from a refractive index of the inner cladding material and the inner cladding region having an effective refractive index Ni, and the outer cladding features having a refractive index that differs from a refractive index of the outer cladding material and the outer cladding region having an effective refractive index No, wherein:
Ni is larger than No at the operating wavelength, the core region is a substantially solid core with a core diameter around or below 4 μ
m and with an effective refractive index Nco being larger than Ni at the operating wavelength, the centre to centre spacing or pitch of the inner cladding features, Λ
i, is around or below 2 μ
m, the inner cladding features have a diameter or cross sectional dimension, di, fulfilling the requirement that di/Λ
l is equal to or below 0.7 and equal to or above 0.2, the centre to centre spacing or pitch of the outer cladding features, Λ
o, is around or below 2 μ
m, and the outer cladding features have a diameter or cross sectional dimension, do, fulfilling the requirement that do/Λ
o is equal to or above 0.4.
Specification