An optical fiber coating apparatus that provides increased gyre stability and reduced gyre strength, thereby providing a more reliable coating application process during fiber drawing includes a cone-only coating die having a conical entrance portion with a tapered wall angled at a half angle α, wherein 2°≤α≤25°, and a cone height L.sub.1 less than 2.2 mm, and a cylindrical portion having an inner diameter of d.sub.2, wherein 0.1 mm≤d.sub.2≤0.5 mm and a cylindrical height of L.sub.2, wherein 0.05 mm≤L.sub.2≤1.25 mm; a guide die having an optical fiber exit, the guide die disposed adjacent the cone-only coating die such that a wetted length (L.sub.5) between the optical fiber exit of the guide die and the entrance of the cone-only coating die is from 1 mm to 5 mm; and a holder for holding the cone-only coating die and the guide die in a fixed relationship defining a coating chamber between the guide die and the cone-only coating die, the coating chamber having an inner radius L.sub.6 from the optical fiber axis to an inner wall of the holder that is from 3 mm to 10 mm.

An optical fiber ribbon comprises a plurality of optical fibers arranged in parallel and a connecting resin layer containing a ribbon resin for coating and connecting the plurality of optical fibers, wherein each of the plurality of optical fibers has an outer diameter of 220 μm or less; each of the plurality of optical fibers includes a glass fiber, a primary resin layer, and a colored secondary resin layer; the colored secondary resin layer contains a cured product of a resin composition containing 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and a content of phosphorus in the colored secondary resin layer is 0.03 mass % or more and 0.30 mass % or less, and an amount of a phosphorus-tin complex at the surface of the colored secondary resin layer is 300 ppm or more and 7000 ppm or less.

An optical fiber ribbon comprises a plurality of optical fibers arranged in parallel and a connecting resin layer containing a ribbon resin for coating and connecting the plurality of optical fibers, wherein each of the plurality of optical fibers has an outer diameter of 220 μm or less; each of the plurality of optical fibers includes a glass fiber, a primary resin layer, and a colored secondary resin layer; the colored secondary resin layer contains a cured product of a resin composition containing 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and a content of phosphorus in the colored secondary resin layer is 0.03 mass % or more and 0.30 mass % or less, and an amount of a phosphorus-tin complex at the surface of the colored secondary resin layer is 300 ppm or more and 7000 ppm or less.

An optical fiber coating apparatus that provides increased gyre stability and reduced gyre strength, thereby providing a more reliable coating application process during fiber drawing includes a cone-only coating die having a conical entrance portion with a tapered wall angled at a half angle α, wherein 2°≤α≤25°, and a cone height L.sub.1 less than 2.2 mm, and a cylindrical portion having an inner diameter of d.sub.2, wherein 0.1 mm≤d.sub.2≤0.5 mm and a cylindrical height of L.sub.2, wherein 0.05 mm≤L.sub.2≤1.25 mm; a guide die having an optical fiber exit, the guide die disposed adjacent the cone-only coating die such that a wetted length (L.sub.5) between the optical fiber exit of the guide die and the entrance of the cone-only coating die is from 1 mm to 5 mm; and a holder for holding the cone-only coating die and the guide die in a fixed relationship defining a coating chamber between the guide die and the cone-only coating die, the coating chamber having an inner radius L.sub.6 from the optical fiber axis to an inner wall of the holder that is from 3 mm to 10 mm.

An optical fiber coating apparatus that provides increased gyre stability and reduced gyre strength, thereby providing a more reliable coating application process during fiber drawing includes a cone-only coating die having a conical entrance portion with a tapered wall angled at a half angle α, wherein 2°≤α≤25°, and a cone height L.sub.1 less than 2.2 mm, and a cylindrical portion having an inner diameter of d.sub.2, wherein 0.1 mm≤d.sub.2≤0.5 mm and a cylindrical height of L.sub.2, wherein 0.05 mm≤L.sub.2≤1.25 mm; a guide die having an optical fiber exit, the guide die disposed adjacent the cone-only coating die such that a wetted length (L.sub.5) between the optical fiber exit of the guide die and the entrance of the cone-only coating die is from 1 mm to 5 mm; and a holder for holding the cone-only coating die and the guide die in a fixed relationship defining a coating chamber between the guide die and the cone-only coating die, the coating chamber having an inner radius L.sub.6 from the optical fiber axis to an inner wall of the holder that is from 3 mm to 10 mm.

Provided is a coated optical fiber and an optical fiber cable capable of suppressing transmission loss (microbend loss) even in an optical fiber having high microbend sensitivity. In the present invention, the degree of freedom of a primary layer 11 represented by the equation (I) and the rigidity of a secondary layer 12 represented by the equation (II) are set in specific ranges, respectively. Thus, the present invention provides a coated optical fiber 1 capable of suppressing the transmission loss even when an optical fiber 10 having high microbend sensitivity such as a BI fiber having a large effective core cross-sectional area A.sub.eff of an optical fiber is used. The present invention can be widely used as a coated optical fiber 1 constituting a coated optical fiber ribbon or as a coated optical fiber 1 housed in an optical fiber cable. Further, an optical fiber cable including such coated optical fibers 1 enjoys the effect of the above-described coated optical fiber 1.
[Math. 1]
β.sub.P×P.sub.ISM≥600  (I)
(S/P)×(S.sub.ISM/P.sub.ISM)≤1,000  (II)

Provided is a coated optical fiber and an optical fiber cable capable of suppressing transmission loss (microbend loss) even in an optical fiber having high microbend sensitivity. In the present invention, the degree of freedom of a primary layer 11 represented by the equation (I) and the rigidity of a secondary layer 12 represented by the equation (II) are set in specific ranges, respectively. Thus, the present invention provides a coated optical fiber 1 capable of suppressing the transmission loss even when an optical fiber 10 having high microbend sensitivity such as a BI fiber having a large effective core cross-sectional area A.sub.eff of an optical fiber is used. The present invention can be widely used as a coated optical fiber 1 constituting a coated optical fiber ribbon or as a coated optical fiber 1 housed in an optical fiber cable. Further, an optical fiber cable including such coated optical fibers 1 enjoys the effect of the above-described coated optical fiber 1.
[Math. 1]
β.sub.P×P.sub.ISM≥600  (I)
(S/P)×(S.sub.ISM/P.sub.ISM)≤1,000  (II)

A fiber optic cable assembly includes first and second cable sections each having a jacket, at least one optical fiber, and multiple strength members. An intermediate cable section includes at least one splice joint as well as bundled sections of strength members of the cable sections formed into bundled sections that overlap and are adhered together. As adhered, the bundled strength members are shorter than the at least one spliced optical fiber in the intermediate section to ensure that the strength members bear tensile loads. A fabrication method includes binding unjacketed segments of strength members of two cable sections into bundled sections of strength members, fusion splicing ends of optical fibers, polymerically overcoating at least one splice joint, and adhering the bundled sections of strength members in an overlapping arrangement. An apparatus for thermoplastically coating cable assembly portions includes a trough for molten thermoplastic material, and a lateral insertion slot defined therein.

A fiber optic cable assembly includes first and second cable sections each having a jacket, at least one optical fiber, and multiple strength members. An intermediate cable section includes at least one splice joint as well as bundled sections of strength members of the cable sections formed into bundled sections that overlap and are adhered together. As adhered, the bundled strength members are shorter than the at least one spliced optical fiber in the intermediate section to ensure that the strength members bear tensile loads. A fabrication method includes binding unjacketed segments of strength members of two cable sections into bundled sections of strength members, fusion splicing ends of optical fibers, polymerically overcoating at least one splice joint, and adhering the bundled sections of strength members in an overlapping arrangement. An apparatus for thermoplastically coating cable assembly portions includes a trough for molten thermoplastic material, and a lateral insertion slot defined therein.

A system for precoating a preform for drawing optical fiber including a diameter sensor to determine a diameter of pulled optical fiber, a cooling system to cool the optical fiber once it is pulled from a furnace, a coating system to apply a coating to the optical fiber once it has cooled and an ultra-violet lamp to cure the coating.