基于幅度调制激光干涉技术的水下声信号测量研究  

Underwater Acoustic Signal Measurement Based on Amplitude-Modulated Laser Interference Technology

作　　者：陆天泽 李宁[1] 黄孝龙[1] 翁春生[1] Lu Tianze;Li Ning;Huang Xiaolong;Weng Chunsheng(National Key Laboratory of Transient Physics,Nanjing University of Science and Technology,Nanjing,Jiangsu 210094,China)

机构地区：[1]南京理工大学瞬态物理国家重点实验室,江苏南京210094

出　　处：《激光与光电子学进展》2021年第9期225-235,共11页Laser & Optoelectronics Progress

基　　金：中国国家留学基金(201906845059);江苏省自然科学基金青年科学基金(BK20190439);中央高校基本科研业务费专项(30919011258)。

摘　　要：为了提高激光干涉测量法的抗干扰能力,提出幅度调制激光干涉测量法。使用可调谐半导体激光器的高频调谐特性对激光信号进行幅度调制,通过水表面反射光与参考光的干涉来获取水下声场的信息,采用锁相放大解调制法实现激光干涉水下声信号的准确反演。对幅度调制激光干涉水下声信号特征进行模拟,搭建基于光纤耦合式的激光干涉水声测试系统。采用10kHz的调制频率驱动中心波长为1405nm的尾纤输出可调谐半导体激光器,并对水下声信号进行测量。结果表明,所提方法能够有效提取水下不同频率和不同强度声信号的振动特征,在频率为2Hz的脉冲噪音的干扰条件下,相较于传统激光干涉测量法。所提方法测量的信噪比提高了10dB以上,增强了水声测量的抗干扰能力。To improve the anti-interference ability of the laser interferometry acoustic measurement method,the amplitude modulated laser interferometry is proposed.Using the high-frequency tuning characteristics of a tunable semiconductor laser to modulate the laser signal amplitude,the underwater sound field information is obtained from the interference of the reflected light on the water surface and the reference light.In addition,the phase-locked amplification and demodulation method is used to obtain the laser interferometry underwater sound signal with accurate inversion.The characteristics of the amplitude-modulated signal are simulated,and a fiber-coupled laser interferometry underwater acoustic test system is built.A modulation frequency of 10 kHz is used to drive a pigtail with a center wavelength of 1405 nm to output a tunable semiconductor laser,and the sound signal is tuned down for measurement.Results show that the proposed method can effectively extract the vibration characteristics of underwater acoustic signals with different frequencies and intensities.Under the interference of pulse noise with a frequency of 2 Hz,the proposed method can be used to measure the signal noise better than the traditional measurement method.The ratio is increased by more than 10 dB,which enhances the anti-interference ability of the underwater acoustic measurement.

关 键 词：测量 激光干涉 水下声信号 光纤光路 调制解调 频谱分析 

分 类 号：O436[机械工程—光学工程]