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US 2004/0170358 A1Published application
Optical fiber coupler and optical fiber therefor
AssigneeFujikura Ltd.
InventorsYuu Ishii, Ryokichi Matsumoto, Daiichiro Tanaka
Life of this patent
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Abstract
An optical fiber coupler is comprised of a fusion-elongated portion 15 in which an optical fiber 11 which is designed and fabricated for use at a wavelength in the vicinity of 1.55 μm and an optical fiber 12 which is designed and fabricated for use at a wavelength in the vicinity of 0.98 μm are fused and elongated. The propagation constant difference between optical fibers 11 and 12 is 10−4 rad/μm or smaller.
Claims14
An optical fiber coupler comprising:
- a plurality of optical fibers including a λ1-band optical fiber and a λ2-band optical fiber, fused together at a fusion-elongated portion, wherein, in the fusion-elongated portion, each of the plurality of optical fibers tapers to a respective narrower outer diameter, relative to an outer diameter of the optical fiber outside the fusion-elongated portion,
- wherein the λ1-band is different from the λ2-band, and
- wherein a propagation constant difference between the optical fibers is 10−4 rad/μm or smaller.
An optical fiber coupler comprising:
- a plurality of optical fibers including a λ1-band optical fiber and a λ2-band optical fiber, fused together at a fusion-elongated portion, wherein, in the fusion-elongated portion, each of the plurality of optical fibers tapers to a respective narrower outer diameter, relative to an outer diameter of the optical fibers outside the fusion-elongated portion,
- wherein the λ1-band is different from the λ2-band, and
- wherein at least outside the fusion-elongated portion, the λ1-band optical fiber is a single mode optical fiber at a wavelength in the vicinity of 0.98 μm,
- wherein at least outside the fusion-elongated portion, the λ1-band optical fiber comprises a first core, a second core surrounding the first core and having a radius within the range of 10 μm or greater, and a cladding surrounding the second core, and
- wherein a relative refractive-index difference of the second core and the cladding is 0.1% or smaller.
2 more elements
An optical fiber for an optical fiber coupler comprising:
- a first core;
- a second core surrounding the first core and having a radius within the range of 10 μm or greater;
- and
- a cladding surrounding the second core,
- wherein a relative refractive-index difference of the second core and the cladding is 0.1% or smaller, and
- wherein the optical fiber for the optical fiber coupler is a single mode optical fiber at a wavelength in the vicinity of 0.98 μm.
3 more elements
An optical fiber coupler comprising:
- a λ1-band optical fiber having a first core with a radius of r1, a second core with a radius of r2 surrounding the first core, and a cladding surrounding the second core;
- a λ2-band optical fiber including a core with a radius of r3, and a cladding surrounding the core;
- and
- a fusion-elongated portion where the A1-band optical fiber and the λ2-band optical fiber are fused together, each of the optical fibers in the fusion-elongated portion tapering to a respective narrower outer diameter, relative to an outer diameter of the optical fibers outside the fusion-elongated portion,
- wherein the λ1-band is lower in wavelength than the λ2-band, and
- wherein r1<r3≦r2.
3 more elements
Dependencies are inferred from the claim text.