All-Fiber Ultrasonic Sensor Based On Ultrathin Silica Reflective Diaphragm

We report a high sensitivity ultrasonic/acoustic sensor based on all-fiber Fabry-Perot interferometer. The proposed sensor is made by splicing a single mode fiber onto a fiber tube with an ultra-thin silica diaphragm, the thickness of which is less 0.9 μm. The diaphragm is fabricated by an electrical arc discharge technique with a fiber tube. The experimental results show that the proposed sensor has a high sensitivity to ultrasound detection as high as 3.68 mV/Pa at 60 kHz. Also it has a wide frequency response, which can reach 30-860 kHz. Due to the sensor fully composed of silica, it is anti-electromagnetic interference and anti-erosion. Moreover, it has a low temperature response, only 8.6 pm/°C.