| 摘要 |
PURPOSE:To improve measurement accuracy and to arrange many sensors closely by connecting couples of optical branching device which can branch light and have different wavelength ranges in series by optical fibers. CONSTITUTION:The couples of optical branching device A3 and optical branching device B4 which can branch light and have the different wavelength ranges are arranged and connected in series by the optical fibers 2, and an OTDR 1 is installed on its one end. Optical fibers 5 for demultiplexing which have open ends are connected to the other-terminal sides of the device A3 and B4. Further, oil 6 which is nearly equal in refractive index to the clad parts of the optical fibers 5 and driving parts 7 are provided. The open end surface of each optical fiber 5 for branching enters and exits from the oil 6 associatively with the motion of the driving part 7 and the intensity of Fresnel reflection on the end surface of the optical fiber 5 varies. Consequently, the motion of the driving part 7 can be detected. The sensors detect the intensity of the Fresnel reflection directly, so loss generated at the sensor part is slight and many sensors can be arranged. |
