An optical fiber protective unit includes: a reticulated tube having openings that are reticulately formed, the reticulated tube being configured to accommodate a plurality of optical fibers inserted through the reticulated tube; a tubular member disposed inside the reticulated tube, the tubular member being configured to accommodate the plurality of optical fibers through the tubular member; and a cylindrical member attached to an end part of the reticulated tube. The cylindrical member has an inner diameter that is larger than an outer diameter of the tubular member.

A fiber optic cable terminal proximally terminates a stub cable carrying one or more optical fibers. The stub cable is structurally adapted to be advanced through at least a portion of a conduit by distally pushing a distal end of the stub cable from a location that is proximal to a proximal end of the conduit and without applying any pulling force at any location that is distal to the proximal end of the conduit.

An optical fiber cable includes: a core including optical fibers; a sheath housing the core; and an interposition layer including fibers between the core and the sheath. Some of the fibers that are disposed from an outer end portion to an intermediate portion in a radial direction of the interposition layer are integrated by a matrix.

An optical fiber unit includes: an optical fiber ribbon in which a plurality of optical fibers are arranged in parallel and connected to each other; a colored bundle tape longitudinally wrapped around an optical fiber ribbon bundle in which a plurality of the optical fiber ribbons are stranded together; and a colored bundle yarn spirally wound around the optical fiber ribbon bundle and the bundle tape.

Embodiments of an optical fiber cable are provided. The optical fiber cable includes an outer jacket, an inner jacket, a porous insulating layer, and at least one optical fiber. The outer jacket has a first thickness between its inner surface and its outer surface. The inner jacket has a second thickness between its inner surface and its outer surface. The inner jacket is disposed within the outer jacket. The porous insulating layer is disposed between the inner jacket and the outer jacket. The porous insulating layer is configured to reduce the transfer of heat to the inner jacket during combustion of the outer jacket. The optical fiber is disposed within the inner jacket. In the optical fiber cable, the first thickness is less than the second thickness, and each of the outer jacket and the inner jacket include at least one flame retardant additive.

An optical cable is provided. The optical cable includes an outer cable body jacket and a plurality of optical fiber subunits. The optical fibers within each subunit are stranded relative to each other and are located within a thin subunit jacket. A plurality of unstranded optical fiber subunits are located within the cable jacket.

An optical fiber cable that includes subunits is provided. The cable has an outer jacket having a thickness of at least 2.0 millimeters and that is made from a fire retardant polymer material having a PHRR value of 222 kw/m.sup.2 when tested in a cone calorimeter measured according to ASTM E1354 with a heat flux of 50 kW/m.sup.2. The cable meets the requirement of UL 1666 burn test for riser cables and the requirements of EN 50399 burn test for CPR class C.sub.ca cables.

A housing structure includes: an optical cable including optical fibers; connector units branching off from the optical cable; and a housing body that houses the connector units. Each of the connector units includes: a first tube through which the optical fibers pass; second tubes through each of which the optical fibers branching off from the first tube pass; and a connector group constituted by optical connectors that are each disposed at an end part of each of the second tubes. The connector group of each of the connector units is disposed at a different position in a length direction from the connector group of any other one of the connector units. The first tube of each of the connector units other than a first connector unit that is shortest among the connector units overlaps in the length direction the connector group of the first connector unit.

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.

An optical fiber having an ink layer that includes an optical brightener is described. The optical brightener is a marker that permits identification of the fiber. The ink layer may also include a pigment, where either or both of the pigment and optical brightener may function as a marker for identifying the fiber. Bundles of two or more optical fibers, each of which includes an ink layer containing an optical brightener, are also described.