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介绍了一种基于Sagnac的分布式光纤声学传感器。这种声学传感器通过光电探测器、数据采集卡、滤波器和音频放大将3×3耦合器处干涉的光信号转换为电信号且实现音频信号的还原。为了研究此分布式光纤声学传感器的性能,分析了基于零频点实验声源扰动定位的原理,并运用快速傅立叶变换将时域信号转化为频域信号显示声源扰动产生的零频点。实验结果表明,基于Sagnac的分布式光纤声学传感系统可以很好地实现声音信号的还原和定位。
A Sagnac-based distributed optical fiber acoustic sensor is introduced. This acoustic sensor converts the optical signal interfering at the 3 × 3 coupler into an electrical signal and restores the audio signal through photodetectors, data acquisition cards, filters and audio amplification. In order to study the performance of the distributed optical fiber acoustic sensor, the principle of disturbance localization based on zero-frequency experimental source is analyzed. The fast Fourier transform is used to transform the time-domain signal into the frequency-domain signal to display the zero-frequency point generated by the source disturbance. Experimental results show that the distributed optical fiber sensing system based on Sagnac can restore and locate the sound signal well.