A jacket is provided to the outer circumference of a cable core, a rip cord, and a tension member. The cable core, the rip cord, and the tension member are collectively covered by the jacket. A wrapping tape is longitudinally placed on the outer circumference of a core part so as to be wound therearound. Thus, immediately after the wrapping tape is longitudinally placed and wound, a wrap part thereof is formed so as to lie substantially straight in the axial direction of an optical fiber cable. In contrast, in an optical fiber cable, the cable core is obtained by combining and intertwining the core part and the wrapping tape. Because of this configuration, the wrap part of the wrapping tape is helically disposed in the longitudinal direction.

This optical fiber cable is a central-core-type cable in which slotted rods are not used, and is composed of a core, a wrapper, a tension member, a ripcord, a sheath, and the like. The core is formed by twisting together a plurality of optical fiber units without back-twisting. The optical fiber units are formed by twisting together a plurality of intermittently-fixed optical fiber ribbons. A direction in which the optical fiber ribbons are twisted together is same as a direction in which the optical fiber units are twisted together.

An optical fiber cable may include a cable jacket, a central tube within the cable jacket, optical fibers within the central tube, and a number of semi-rigid rods around the central tube. Each rod may have a cross-sectional shape with an aspect ratio of at least 2:1. The rods may be helically applied around the central tube.

The present disclosure provides an intermittently bonded optical fibre ribbon. The intermittently bonded optical fibre ribbon includes a plurality of optical fibres. The plurality of optical fibres has bonded regions and un-bonded regions between adjacent optical fibres of the plurality of optical fibres. The bonded regions have a plurality of bonds. Each bonded region has a bond of the plurality of bonds joining the adjacent optical fibres such that the bond does not cover a top optical fibre region and a bottom optical fibre region of the plurality of optical fibres.

A single mode optical fiber is provided that includes a core region having an outer radius r.sub.1 and a maximum relative refractive index Δ1.sub.max. The single mode optical fiber has a bend loss at 1550 nm for a 15 mm diameter mandrel of less than about 0.75 dB/turn, has a bend loss at 1550 nm for a 20 mm diameter mandrel of less than about 0.2 dB/turn, and a bend loss at 1550 nm for a 30 mm diameter mandrel of less than 0.002 dB/turn. Additionally, the single mode optical fiber has a mode field diameter of 9.0 microns or greater at 1310 nm wavelength and a cable cutoff of less than or equal to about 1260 nm.

An optical fiber cable includes: a plurality of optical fibers or a plurality of optical fiber ribbons; a cable sheath inside which a plurality of the optical fibers or a plurality of the optical fiber ribbons are housed; and four or more tensile strength member units which are provided so as to be embedded inside the cable sheath, and in which two or more tensile strength members are paired with each other, in which the four or more tensile strength member units are respectively provided at locations facing each other with a center of the optical fiber cable interposed therebetween in a cross section in a radial direction of the optical fiber cable, and in which a cable outer diameter of the optical fiber cable is 6 mm or more and 16 mm or less.

The present disclosure provides a matrix material for a rollable optical fibre ribbon. The rollable optical fibre ribbon includes a plurality of optical fibres and the matrix material. In addition, each of the plurality of optical fibres is placed parallel to other optical fibres of the plurality of optical fibres. Further, the matrix material joins the plurality of optical fibres. Furthermore, the matrix material has different glass transition temperature at different pressures.

A fiber optic assembly is provided including a support substrate having a substantially flat surface and a signal-fiber array supported on the support substrate. The signal-fiber array includes a plurality of optical fibers. At least some of the optical fiber of the plurality of optical fibers includes a first datum contact disposed between the optical fiber and an adjacent optical fiber and each of the optical fibers of the plurality of optical fibers includes a second datum contact disposed between each of the optical fibers of the plurality of optical fibers and the support substrate. A first datum surface is disposed at a top surface of each of the plurality of optical fibers opposite the support surface.

An optical cable includes a plurality of buffer tubes, each of the buffer tubes includes a flexible ribbon, the flexible ribbon including a plurality of optical fibers, the flexible ribbon being wrapped with a finished tape.

Provided is an optical fiber having identification mark, which includes an optical transmission medium (exemplified by glass fiber) including a core part and a cladding part, a primary resin layer coating the optical transmission medium, and a secondary resin layer coating the primary resin layer, in which identification marks for optical fiber identification (exemplified by continuous identification mark) are provided on a surface of the secondary resin layer at a predetermined interval along an axial direction of the optical transmission medium. An effective area of the optical transmission medium at a wavelength of 1550 nm is 90 μm.sup.2 or more, the predetermined interval is 100 mm or more and 500 mm or less, and a Young's modulus of the primary resin layer is 0.9 MPa or less.