为了实现低频水表面声波振幅准确探测和时变声信号的跟踪识别, 提出了一种基于相位解调的激光干涉探测方法。该方法在参考光路中引入高频载波, 利用相位生成载波技术的反正切解调算法, 并结合高频载波初相位和调制深度的测定, 可实现水表面声波的准确识别。在实验室环境下搭建了一套水表面声波探测系统, 实验结果表明: 该方法对水表面声波微振幅的测量重复性不超过1 nm。同时该系统能够实时跟踪水下声源的变化, 对幅度受到正弦调制的水下声源信号进行了水表面声波振幅检测, 实验结果证明了该方法识别时变声信号的正确性。

A laser interference detection method based on phase demodulation had been developed to measure the amplitude of low frequency water surface acoustic waves and identify the changed sound source. Water surface acoustic wave amplitude measurement was achieved by introducing a high frequency carrier into the reference optical path, using the arctangent demodulation algorithm of phase-generated carrier technology, in combination with the determined of initial phase and the modulation depth of the carrier. A set of amplitude measurement system was constructed under laboratory conditions, and the experimental results show that this method can accurately identify the amplitude, and the measurement repeatability is better than 1 nm. The detection result of the amplitude-modulated sound source signal indicates that the method can accurately track the change of the water surface acoustic wave amplitude, which proves the correctness of the method for identifying the changed sound source.