Dual-fiber-Bragg gratings accelerometer for the detection of geosound caused by debris flow

Abstract. The cantilever-beam accelerometer based on dual-fiber-Bragg gratings (FBGs) is proposed to detect the geosound caused by debris flow. The structure and working principle of the accelerometer are demonstrated. Dual FBGs are introduced to improve the sensitivity and frequency response of the accelerometer. By using a bend insensitive optical fiber and ultrathin coating, the sensitivity and serial multiplexing performance of the sensor are improved remarkably. Experimental results show that the accelerometer, with a sensitivity of 900  pm/g and the natural frequency of 280 Hz, can effectively detect the geosound caused by debris flow.