基于斐索干涉的超弱光纤光栅水听器阵列实验研究

Experimental Study on Ultra-Weak Fiber Bragg Grating Hydrophone Arrays Based on Fizeau Interference

研究了一种基于斐索干涉的超弱光纤光栅(uwFBG)水听器阵列系统。通过拉丝塔在线制备光纤光栅技术构建超弱光纤光栅水听器阵列,使用反正切算法解调信号,实现了2~2000Hz宽频带内水声信号的振幅、频率和相位的同时测量。在频率为2Hz时,系统水声信号的相位声压灵敏度可达-135.81dB(re rad/μPa),灵敏度为2755.49(μPa/√Hz),信噪比为43.785dB。传感器复用实验结果证实该系统可以同时解调不同位置的水声信息,系统的相位声压灵敏度随着传感器腔长的增加而增加,且具有很好的稳定性,表明系统在高灵敏度水声传感、甚低频声学探测、深海监测等方面具有广阔的应用前景。

Herein,an ultra-weak fiber Bragg grating hydrophone array system based on Fizeau interference is demonstrated.The ultra-weak fiber Bragg grating hydrophone array is constructed via on-line preparation of a fiber Bragg grating using a drawing tower.The amplitude,frequency,and phase of underwater acoustic signals in a wide frequency range of 2-2000 Hz are simultaneously measured using the signal demodulated by the arc-tangent algorithm.The phase acoustic-pressure sensitivity of the system hydroacoustic signals at 2 Hz reaches-135.81 dB(re rad/μPa).The sensitivity is 2755.49μPa/√Hz,and the signal-to-noise ratio is 43.785 dB.The experimental results of sensor multiplexing prove that the system can demodulate underwater acoustic information at different locations.Furthermore,the phase acousticpressure sensitivity of the system increases with the increasing cavity length of the sensor.The system exhibits very good stability,indicating the possibility of extensive applications in high-sensitivity underwater acoustic sensing,very low frequency acoustic detection,deep-sea monitoring,and other fields.