| 摘要 |
PURPOSE:To secure the extra connection length of an optical fiber core and to cope with variation during branching and downward leading by varying the twisting rate of optical fiber cores in an optical fiber unit in the direction of the unit axis, and arranging places where the twisting rate is large at desired intervals. CONSTITUTION:Optical fiber cores 21 are twisted around a unit center material 22 and a pressing material 28 is wound around them to constitute the optical fiber unit 24. Then, the twisting rate of the optical fiber cores 21 is varied in the axial direction of the unit 24 to arrange places 39 where the twisting rate is large at desired intervals. When the optical fiber unit 24 is branched from the optical fiber cable, the center part of a place 39 where the twisting rate is large is cut to release an optical fiber core 21. |
