Optical fiber unit, optical fiber branching method, and optical fiber cable

Abstract

An optical fiber unit that bundles a bundle of optical fiber cores with a bundle material, improves workability when taking out the optical fiber cores, and suppresses an increase in transmission loss even if tension is applied to the bundle material. The optical fiber unit of the present invention is characterized in that it includes a plurality of optical fiber core wires, and three or more bundle materials that bundle the plurality of optical fiber core wires, and the first bundle material among the plurality of bundle materials is wound around the arranged along the length direction of the bundle of optical fiber core wires on the outer periphery of the bundle of optical fiber core wires, is joined to the second bundle material at a contact point with the second bundle material, and is different from the The contact point of the third beam material of the second beam material is joined to the third beam material, at the contact point of the second beam material and the contact point of the third beam material Reversing the winding direction of the bundle relative to the optical fiber cores.

Description

technical field [0001] The invention relates to an optical fiber unit, an optical fiber branching method and an optical fiber cable. Background technique [0002] There is known a technique in which an optical fiber cable is constituted by an aggregate of optical fibers in which a plurality of optical fiber cores are bundled as an optical fiber unit. At this time, it is generally a method to prevent loosening of the bundle of optical fiber core wires by winding a thick coil (bundle material) around the bundle of optical fiber core wires, and to identify the optical fiber unit by the color of the bundle material. [0003] Regarding such a bundle material, Patent Document 1 discloses a technique in which a plurality of bundle materials are helically wound around a bundle of optical fiber cores, and the bundle of optical fiber cores is bundled by joining the bundle materials to each other. In addition, in Patent Document 2 (particularly, FIG. 7 of Patent Document 2), it is dis...

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Problems solved by technology

In this case, it is necessary to pull the bundle material into a helical shape, so the operation of taking out the optical fiber core is troublesome, and there is a possibility that the optical fiber core wire may be broken due to fingers caught in the optical fiber core wire during the pulling operation.

[0007] In addition, when the bundle material is wound helically around the bundle of optical fiber core wires, or when two bundle materials are wound in an SZ shape around the bundle of a plurality of optical fiber core wires as in Patent Document 2 , if tension is applied to the bundle material, the fiber core will meander, which may increase the transmission loss

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