| 摘要 |
PURPOSE:To make injection easy and prevent the deterioration of optical fibers by disposing helical spacers on the inside circumference of the pipe of the cable, loosely inserting optical fiber cores in the central part thereof and injecting and packing tacky resins therein. CONSTITUTION:Helical spacers 3 are disposed on the inside circumference of a pipe 2 or are integrated with the pipe 2. Optical fiber cores 4 are loosely inserted. The tacky silicone resin, polyurethane resin or tacky foamed urethane resin or the like is respectively injected from one end of this pipe. Since the packed resin has good bending characteristic, the defect that the optical fibers are loaded with stress owing to thermal fluctuations with time and are thereby degraded is obviated. In addition, the resin to be injected is put in through the helical spacers and since this causes the resin to be sufficiently infiltrated to the inside, the resin effectively acts as a gas dam. Unlike conventional gas dam cables, the protruding portions may be eliminated. |
