Abstract: An optical fiber ribbon includes a plurality of optical fiber cores arranged in parallel in a direction orthogonal to a longitudinal direction of the optical fiber cores, and a coupling member configured to couple the plurality of optical fiber cores. In the optical fiber ribbon, a plurality of coupled sections and a plurality of separate sections are alternately provided in the longitudinal direction. Each of the plurality of coupled sections is in a state in which all of the adjacent optical fiber cores are coupled by the coupling member. Each of the plurality of separate sections is in a state in which at least two of the optical fiber cores adjacent to each other are not coupled by the coupling member.

Abstract: An optical fiber cable includes a central tensile strength member, a plurality of optical fibers disposed around the central tensile strength member, a set of tensile strength members arranged outside the plurality of optical fibers, and a sheath disposed outside the plurality of optical fibers, in which at least four sets of the tensile strength member are spaced apart from one another and embedded in the sheath.

Abstract: A method for laying an optical fiber cable including a cable core, a cable sheath that includes an inner jacket and an outer jacket, and a tensile strength member, a first kinetic friction coefficient of the outer jacket being smaller than a second kinetic friction coefficient of the inner jacket to the duct, first flame retardance of the inner jacket being higher than the second flame retardance of the outer jacket. The method includes wiring the optical fiber cable in an outdoor side via the duct, drawing the optical fiber cable from the outdoor side to an indoor side, making a part of the optical fiber cable as an optical fiber cable for indoor wiring by removing the outer jacket after the drawing of the optical fiber, and wiring the optical fiber cable for indoor wiring in the indoor side.

Abstract: An optical fiber cable includes a plurality of optical fibers, a plurality of water-absorbent fibers, and a sheath covering a periphery of the plurality of optical fibers and the plurality of water-absorbent fibers. A ratio of areas of the water-absorbent fibers to an area of an accommodating portion in an inner side of the sheath in a cross section orthogonal to a longitudinal direction of the optical fiber cable is 1% or more and 5% or less, and a maximum value of an area of a gap portion surrounded by the optical fibers in the cross section is 1.0 mm2 or less.

Abstract: An optical fiber cable includes optical fiber ribbons and a sheath covering a periphery of the plurality of optical fiber ribbons. Each of the optical fiber ribbon includes optical fibers, and a connected portion and a non-connected portion are intermittently provided in the longitudinal direction. Each optical fiber includes a glass fiber and a coating portion. A ratio of an inner diameter to an outer diameter of the sheath is 0.75 or more. A ratio of a total area of glasses in an optical fiber ribbon accommodating portion to an area of the optical fiber ribbon accommodating portion is 15% or more and 25% or less, the number of the optical fibers in the optical fiber cable is 3000 or more, and the outer diameter of the sheath is 50 mm or less.

Abstract: An optical fiber cable includes a plurality of optical fibers, a tensile strength member set that is disposed along the plurality of optical fibers in a longitudinal direction of the optical fiber cable, and a sheath that covers the plurality of optical fibers from outside and encloses the tensile strength member set in the sheath. In the optical fiber cable, at least four tensile strength member sets are embedded in the sheath in a state where the four tensile strength member sets are apart from each other in a radial direction of the optical fiber cable, the sheath includes a flame-retardant inorganic substance and a release agent, and a distance from one of the four tensile strength member sets to a surface layer of the sheath is 0.5 mm or more.

Abstract: An optical fiber unit includes a plurality of optical fibers, a fibrous filler disposed along the plurality of optical fibers, and a resin film covering the plurality of optical fibers and the fibrous filler from outside. In the optical fiber unit, the resin film has a film thickness smaller than a diameter of the fibrous filler.

Abstract: An optical fiber ribbon includes a plurality of optical fiber cores arranged in parallel in a direction orthogonal to a longitudinal direction of the optical fiber cores, and a coupling member configured to couple the plurality of optical fiber cores. In the optical fiber ribbon, a plurality of coupled sections and a plurality of separate sections are alternately provided in the longitudinal direction. Each of the plurality of coupled sections is in a state in which all of the adjacent optical fiber cores are coupled by the coupling member. Each of the plurality of separate sections is in a state in which at least two of the optical fiber cores adjacent to each other are not coupled by the coupling member.

Abstract: Provided is an optical fiber ribbon in which four or more optical fibers including a colored layer are arranged in parallel. A color of the colored layer includes: a first color for coloring the colored layer of the optical fiber arranged on one end side in an arrangement direction; and a second color which is a color different from the first color and which colors the colored layer of other optical fibers not colored with the first color. The number of optical fibers colored with the first color is different from the number of optical fibers colored with the second color.

Abstract: An intermittent-connection-type optical fiber ribbon includes: a plurality of optical fiber core wires that are disposed in parallel; a connecting resin that is coated on surfaces of the plurality of optical fiber core wires; and slits that are provided intermittently in the connecting resin partially between the optical fiber core wires in a longitudinal direction, and a marking is on the connecting resin.

Abstract: An intermittent-connection-type optical fiber ribbon includes: a plurality of optical fiber core wires that are disposed in parallel; a connecting resin that is coated on surfaces of the plurality of optical fiber core wires; and slits that are provided intermittently in the connecting resin partially between the optical fiber core wires in a longitudinal direction, and a marking is on the connecting resin.