School of Physics, Northwest University, Xi'an 710127, China.
Sensors (Basel). 2018 Jun 14;18(6):1942. doi: 10.3390/s18061942.
A novel kind of fiber optic ultrasonic sensor based on matching fiber Bragg gratings (FBGs) is proposed and demonstrated. The sensors consist of a pair of matching FBGs fixed to a special bracket. The bracket plays a role in stretching and squeezing the FBGs, with the push⁻pull effect efficiently coupling the ultrasonic signal to the sensor, thus, improving the sensor’s sensitivity. Side-band filtering technology-based intensity interrogation was used to detect ultrasounds in water. With the synergic effect of the matching FBGs, the sensor performed with a high signal-to-noise ratio (56.9 dB at 300 KHz, 53 dB at 1 MHz and 31.8 dB at 5 MHz) and the observed ultrasonic sinusoidal signals were undistorted and distinguishable in the time domain.
提出并演示了一种基于匹配光纤布拉格光栅（FBG）的新型光纤超声传感器。该传感器由一对固定在特殊支架上的匹配 FBG 组成。支架在拉伸和挤压 FBG 方面发挥作用，推挽效应有效地将超声信号耦合到传感器中，从而提高了传感器的灵敏度。基于边带滤波技术的强度检测用于检测水中的超声波。在匹配 FBG 的协同作用下，该传感器具有高信噪比（300 kHz 时为 56.9 dB，1 MHz 时为 53 dB，5 MHz 时为 31.8 dB），在时域中观察到的超声正弦信号未失真且可区分。
