Optical fiber
AssigneeFujikura Ltd.
InventorRyo Maruyama
Life of this patent
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Abstract
An optical fiber includes: a core; a depressed layer surrounding the core; and a cladding surrounding the depressed layer. A refractive index profile of the core is an α-th power distribution having an index α of 1.0 or more and 2.9 or less. A relative refractive index difference Δ− of the depressed layer with respect to the cladding has an absolute value |Δ−| that is 0.05% or more and 0.15% or less. A ratio r1/r2 of a radius r1 of the core to an outer radius r2 of the depressed layer is 0.35 or more and 0.60 or less. A cable cutoff wavelength λcc of 22 m is less than 1.26 μm. A mode field diameter at a wavelength of 1.31 inn is larger than 8.6 inn and smaller than 9.5 μm.
Claims8
An optical fiber comprising:
- a core;
- a depressed layer surrounding the core;
- and
- a cladding surrounding the depressed layer,
- wherein a refractive index profile of the core is an α-th power distribution having an index α of 1.0 or more and 2.9 or less,
- wherein a relative refractive index difference Δ−of the depressed layer with respect to the cladding has an absolute value |Δ−| that is 0.05% or more and 0.15% or less,
- wherein a ratio r1/r2 of a radius r1 of the core to an outer radius r2 of the depressed layer is 0.35 or more and 0.60 or less,
- wherein a cable cutoff wavelength λcc of 22 m is less than 1.26 μm,
- wherein a mode field diameter at a wavelength of 1.31 μm is larger than 8.6 μm and smaller than 9.5 μm and
- wherein the index α is obtained by calculating the α-th power distribution that minimizes a square error of an actual refractive index profile n′(r) of the optical fiber in a range of 0 ≤r≤r0,
- where r is a distance from a central axis of the optical fiber, and r0 is a radius of the optical fiber for obtaining a minimum value of a first order differential dn′(r)/dr of n′(r).
Dependencies are inferred from the claim text.