Improving the performance of Sagnac interferometer for debris flow monitoring system

In this paper, we investigate the performance enhancement of fiber-optic sensor based on Sagnac interferometer for debris flow monitoring system. First, we investigate the sensing head mandrel and get 60 laps mandrel which is the best number of wrapping fiber coils. Then we study two difference length delay fibers of the dual-loop Sagnac interferometer structure to improve the sensitivity and accuracy. From the experimental results, we can find the length of delay fiber-1 with 3 kilometers long is the best selection, and the length of delay fiber-2 has little impact on the sensing results.