| 摘要 |
PROBLEM TO BE SOLVED: To improve the coated optical fiber taking-out performance and side pressure resistance at a terminal together with laying performance when an optical unit is fed and laid into a pipeline by using air flow. SOLUTION: The structure, in which a foamed resin 3 existing in the spacing parts of wires arranged on the outermost periphery of an assemblage of the wires consisting of plural pieces of the coated optical fibers 2 or the coated optical fibers 2 and intervening wires bulges toward the outer side to form a major diameter part 4 and the foamed resin 3 in the middle of this major diameter part 4 forms a minor diameter part 5, is adopted as the structure of the optical unit having the assemblage described above and a sheath consisting of the foamed resin 3 with which the outer periphery of the assemblage is directly coated. As a result, the laying of the unit to the long-sized pipeline is made possible and the minor diameter part 5 tears easily and, therefore, the foamed resin 3 may be easily removed and the taking out of the coated optical fibers 2 is made simple. In addition, the major diameter part 4 acts as a buffer layer with respect to side pressures and, therefore, the excellent side pressure resistance is the obtained and the gripping and fixing of the terminal is facilitated.
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