DISASTER PREVENTION FIBER OPTIC SENSOR AND DEVICE FOR LANDSLIDE MONITORING

摘要

PROBLEM TO BE SOLVED: To provide a landslide monitoring device which is prevented from being influenced by a temperature change of environment.;SOLUTION: A tension information is obtained without using a spectrum analyzer by: arranging two fiber Bragg grating (FBG) 5 and 7 having a different reflection wavelength each other at two points those located on a same fiber optic 3 loaded with equal tension but in a different temperature environment; obtaining a tension information by utilizing a fact that information on tension changing is of an in-phase type in response signals of two FBG 5 and 7; and utilizing additional pair of FBG 6 and 8 for a use of reference. The pair of the reference FBG has the same pair of the reflection wavelength as that of the pair of a sensing FBG. By passing a reflectance of the sensing FBG through the corresponding reference FBG respectively, changing in wavelength is converted to changing in light power. The converted data goes through analog signal process, or is converted to digital signal by AD conversion and processed in digital signal processing with defined algorithm.;COPYRIGHT: (C)2012,JPO&INPIT