| 摘要 |
PROBLEM TO BE SOLVED: To absorb the extra lengths generated in coated optical fibers and to suppress the longitudinal movement of the extra lengths of the coated optical fibers by specifying the sum total of the sectional areas of plural pieces of the coated optical fibers to the sectional areas of the spaces where the coated optical fibers of the grooves housing the coated optical fibers are movable at a specific rate. SOLUTION: The grooves 3 are formed at the spacer 2 by extruding a synthetic resin, for example, polyethylene. The grooves 3 are formed to spiral grooves in one direction or inverted spiral grooves. The coated optical fibers 4 are housed in the respective grooves 3. The coated optical fibers 4 are not required to be housed in part of the grooves 3. The filling rate in the grooves 3 housing the coated optical fibers 4 is set at 10 to 50%. If the filling rate is lower than 10%, the coated optical fibers 4 in the grooves 3 are easily movable and in the case of perpendicular laying in a building, etc., the extra length pools are liable to arise. If the filling rate exceeds 50%, the bending of a small radius of curvature is liable to arise at the coated optical fibers 4 when the extra lengths are added. |
