| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To detect a submerged spot of an optical fiber cable which is one of damage causes of an optical fiber. <P>SOLUTION: Raman scattered light which is one of backscattered lights in the optical fiber is utilized. Pulsed light is allowed to enter the optical fiber to be diagnosed, and the Raman scattered light is detected and the difference between incident timing of the pulse and detection timing of the scattered light is detected. The diagnostic position of the optical fiber can be detected from the difference. The temperature distribution of the optical fiber can be detected from the intensity ratio between Stokes scattered light and anti-Stokes scattered light. Hereby, the temperature distribution in the length direction of the optical fiber can be detected. The distribution of a temperature change with age in the length direction of the optical fiber can be detected by detecting the temperature distribution continuously. When a submerged spot exists in the optical fiber, the spot has a large specific heat compared with a non-submerged spot, and thereby has a slow temperature change or a small change width or change speed of the temperature, to thereby detect submergence. <P>COPYRIGHT: (C)2004,JPO</p> |
