Abstract: An optical fiber manufacturing method includes setting a first holding member and a rod inside a glass pipe, the first holding member made of glass and having plural holes formed, so that the rod is supported by the first holding member; filling glass particles between the rod and a glass pipe inner wall; holding the rod such that the rod and the filled glass particles are enclosed by the glass pipe inner wall and the first and second holding members, and sealing one end of the glass pipe and manufacturing an intermediate; and manufacturing an optical fiber from the intermediate, wherein a bulk density of the first and second holding members is set with reference to a bulk density of a filling portion made from the glass particles, and the predetermined range is determined according to a core diameter permissible variation range in its longitudinal direction.

Abstract: An optical fiber manufacturing method includes setting a first holding member and a rod inside a glass pipe, the first holding member made of glass and having plural holes formed, so that the rod is supported by the first holding member; filling glass particles between the rod and a glass pipe inner wall; holding the rod such that the rod and the filled glass particles are enclosed by the glass pipe inner wall and the first and second holding members, and sealing one end of the glass pipe and manufacturing an intermediate; and manufacturing an optical fiber from the intermediate, wherein a bulk density of the first and second holding members is set with reference to a bulk density of a filling portion made from the glass particles, and the predetermined range is determined according to a core diameter permissible variation range in its longitudinal direction.

Abstract: An optical fiber preform manufacturing method includes: supporting a drilling jig in a radial direction of a preform that is cylinder-shaped; moving the drilling jig in a longitudinal direction of the preform; and forming a plurality of slits each extending in the longitudinal direction and each directed from an outer side of the preform toward a center the preform, and a plurality of holes each extending in the longitudinal direction and each connecting with an end of one of the plurality of slits in a depth direction of the one of the plurality of slits.

Abstract: An optical fiber has a refractive index profile approximated by n(r)=n1[1-2(?1/100)(r/a)^?]1/2 when 0<r?a, and n(r)=n1[1-2(?1/100)]1/2 when a<r, where n1 is refractive index at the center of a core, ?1 is relative refractive index difference between the center of the core and a cladding, a is radius of the core, ? is refractive index profile parameter, and ^ represents an exponential. ? is 1.95 to 2.15. The relative refractive index difference is 1.5% or larger. A diameter of the core is 20 ?m to 45 ?m. A diameter of the cladding is 70 ?m to 90 ?m. A bending loss at 850 nm when bending the optical fiber with a curvature radius of 5 mm is 0.1 dB/turn or lower.

Abstract: An optical fiber preform manufacturing method includes: supporting a drilling jig in a radial direction of a preform that is cylinder-shaped; moving the drilling jig in a longitudinal direction of the preform; and forming a plurality of slits each extending in the longitudinal direction and each directed from an outer side of the preform toward a center the preform, and a plurality of holes each extending in the longitudinal direction and each connecting with an end of one of the plurality of slits in a depth direction of the one of the plurality of slits.

Abstract: An optical fiber, made of silica-based glass, comprising a core and a cladding, each of the optical fiber having a mode field diameter of 5.5 ?m or larger at a wavelength of 1100 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1100 nm when the optical fiber is bent with a curvature radius of 2 mm.

Abstract: An optical fiber ribbon includes a plurality of optical fibers, each includes a glass optical fiber coated with a fiber coating, that are arranged in parallel, and a ribbon coating that coats the optical fibers arranged in parallel. The optical fiber ribbon has a thickness equal to 300 ?m or less. The fiber coating is made of a non-flame-resistant ultraviolet curable resin. The ribbon coating has a thickness equal to 40 ?m or more and is made of a flame resistant resin.

Abstract: An optical fiber is made of silica-based glass, and includes a core and a cladding. The optical fiber has a mode field diameter of 5.4 micrometers or larger at a wavelength of 1300 nanometers, transmits light with a wavelength of 1250 nanometers in a single mode, and has a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nanometers when the optical fiber is bent with a curvature radius of 1 millimeter.

Abstract: An optical fiber, made of silica-based glass, comprising a core and a cladding. The optical fiber having a mode field diameter of 6.5 ?m or larger at a wavelength of 1300 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nm when the optical fiber is bent with a curvature radius of 1.5 mm.

Abstract: An optical fiber, made of silica-based glass, comprising a core and a cladding, each of the optical fiber having a mode field diameter of 5.5 ?m or larger at a wavelength of 1100 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1100 nm when the optical fiber is bent with a curvature radius of 2 mm.

Abstract: An optical fiber has a refractive index profile approximated by n(r)=n1[1?2(?1/100)(r/a)??]1/2 when 0<r?a, and n(r)=n1[1?2(?1/100)]1/2 when a<r, where n1 is refractive index at the center of a core, ?1 is relative refractive index difference between the center of the core and a cladding, a is radius of the core, ? is refractive index profile parameter, and ? represents an exponential. ? is 1.95 to 2.15. The relative refractive index difference is 1.5% or larger. A diameter of the core is 20 ?m to 45 ?m. A diameter of the cladding is 70 ?m to 90 ?m. A bending loss at 850 nm when bending the optical fiber with a curvature radius of 5 mm is 0.1 dB/turn or lower.

Abstract: An optical fiber is made of silica-based glass, and includes a core and a cladding. The optical fiber has a mode field diameter of 5.4 micrometers or larger at a wavelength of 1300 nanometers, transmits light with a wavelength of 1250 nanometers in a single mode, and has a bending loss of 1 dB/turn or smaller at a wavelength of nanometers when the optical fiber is bent with a curvature radius of 1 millimeter.

Abstract: An optical fiber ribbon includes a plurality of optical fibers, each includes a glass optical fiber coated with a fiber coating, that are arranged in parallel, and a ribbon coating that coats the optical fibers arranged in parallel. The optical fiber ribbon has a thickness equal to 300 ?m or less. The fiber coating is made of a non-flame-resistant ultraviolet curable resin. The ribbon coating has a thickness equal to 40 ?m or more and is made of a flame resistant resin.

Abstract: An optical fiber, made of silica-based glass, comprising a core and a cladding. The optical fiber having a mode field diameter of 6.5 ?m or larger at a wavelength of 1300 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nm when the optical fiber is bent with a curvature radius of 1.5 mm.