| 摘要 |
PURPOSE:To limit the broken point of the optical fiber cable when the cable is broken at the mid-point by bending at least a piece of optical fiber among the optical fibers at the mid-point of a forward path to form a return path. CONSTITUTION:For example, the optical fiber cable 1 has 4 pieces of the optical fibers 11 to 14, of which the optical fibers 11 and 12 start from one end A of the optical fiber cable and arrive at the other end D and the optical fiber 13 forms the forward and return path. Namely, this optical fiber starts from the end A, returns at the point C to reach the original end A and the optical fiber 14 is constituted to start from the end A, to return at the point B and to arrive at the same end A. The optical fibers 11 and 12 are used for optical transmission and the optical fibers 13 and 14 are used for searching the broken point in the case of using the optical fiber cable 1 as the optical transmission line. the broken point is limited to a specific section in this case when the optical fiber cable is broken. |
