Fiber optic hydrophones have been widely used in underwater sounding, vibration detection and marine geological exploration due to their high sensitivity, wide frequency response range and strong anti-electromagnetic interference capability. In this paper, an adaptive filtering scheme based on Least Mean Square algorithm (LMS) is proposed to improve the detection sensitivity of hydrophones. Aiming to eliminate noise interference, a reference interferometer with the same parameters as the signal interferometer is added to the optical structure. Then, two 3 × 3 couplers are placed to demodulate the sensing signal and the noise signal respectively. Finally the adaptive filtering process is adopted to eliminate the noise effectively. The experimental results show that the proposed scheme can reduce the harmonic distortion signal and the noise signal. The suppression capability of the harmonic distortion signals at 1000 Hz is about 19 dB, and the signal-to-noise ratio is improved by about 23 dB.

光纤水听器具有灵敏度高，频率响应范围广，抗电磁干扰能力强等优点，已广泛用于水下测深，振动检测和海洋地质勘探中。提出了一种基于最小均方算法的自适应滤波方案，以提高水听器的检测灵敏度。为了消除噪声干扰，将与信号干涉仪具有相同参数的参考干涉仪添加到光学结构中。然后，放置两个3×3耦合器分别解调传感信号和噪声信号。最后采用自适应滤波处理，有效地消除了噪声。实验结果表明，该方案可以降低谐波失真信号和噪声信号。