Development of a multi-interval displacement sensor using Fiber Bragg Grating technology

Sanada, Hiroyuki; Sugita, Yutaka ; Kashiwai, Yoshio*

In this paper, application of the multi-interval displacement sensor using Fiber Bragg Grating (FBG) technology in the Horonobe URL is described. Laboratory tests were carried out to obtain the relational expression computed from the relationship of the variation in the Bragg wavelength, temperature and displacement. From the results of laboratory test, accuracy of sensor was evaluated better than 0.5% of the measurement range. In situ monitoring at the Horonobe URL using the developed sensor was carried out in parallel with nearby monitoring using a conventional extensometer, which is electrical signal system type, for verification of the developed sensor. In situ test results indicate that the displacement values from both the developed sensor and the conventional extensometer are almost equivalent. One of the advantages of the developed sensor was that there was no noise in the obtained monitoring data, while the data from the conventional extensometer shows some noise.