为了满足现代水声传感对光纤水听器系统大动态范围的要求, 研究了外差检测技术, 提出了外差-反正切的解调方案。通过软件仿真模拟, 分析了一定噪声下外差检测方案中的干涉信号特征和解调结果特征, 成功解调出1 kHz的声信号。同时展示了在一定参数下采用外差检测法可以使得光纤水听器系统的解调信号频率达到7 kHz和振幅达到40 rad。最后搭建了基于外差检测技术的干涉型光纤水听器系统, 成功解调出1 kHz的待测信号, 并展示了光纤水听器系统实验的干涉信号特征和解调结果特征, 这与理论仿真具有相同的结果, 验证了外差实验的正确性和可行性。对干涉型光纤水听器的研究和应用具有参考价值。

To meet modern acoustic sensing requirements for large dynamic range of a fiber-optic hydrophone system, the paper has a research on heterodyne detection technology. A demodulation algorithm heterodydne-arctangent is demonstrated in details. By simulating heterodydne detection scheme, the characteristics of the interference signal and the demodulation results are analyzed. The acoustic signals can successfully be demodulated. Meanwhile, the demodulation performance is showed that demodulated signal frequency is up to 7 000 Hz and amplitude is up to 40 rad by heterodydne in certain parameters setting. Finally, in the fiber-optic Michelson hydrophone system experiment based on heterodydne detection scheme, the signal at 1 kHz can successfully be detected and demodulated. At the same time, it shows the characteristics of the interference signal and the demodulation results in the experiment, which are the same as ones in the simulation. It proves that heterodydne experiment is correctness and practicability. It is of great significance for studying and applying for a fiber-optic hydrophone system.