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介绍了激光多普勒振动计(LDV)用于水下声光通信的应用背景,阐述了激光多普勒振动计的工作原理和两种相干检测方式。采用零差的相干探测方式,设计并实现了一套光纤结构的激光多普勒振动计。为了证明系统能够应用于水下声光通信,进行了对水下声源发出的声波频率和强度的探测实验。通过对实验数据的分析得出:第一,系统能够检测出水下声源发出的声波频率,对7kHz附近的10个声波频率的测量标准偏差小于8Hz;第二,系统探测信号强度与水下声源发声的声压级成指数关系,对于水下目标通信所用的3.5kHz和7kHz声波频段的最小探测能力分别达到146.2dB和150.8dB声压级。
The application background of laser Doppler vibrometer (LDV) for underwater acoustooptic communication is introduced. The working principle and two coherent detection methods of laser Doppler vibrometer are described. Using homodyne detection method of homodyne, a set of laser Doppler vibrometer with fiber structure was designed and realized. In order to prove that the system can be applied to underwater acousto-optic communication, the acoustic frequency and intensity detection experiments on underwater sound sources were carried out. Through the analysis of the experimental data, we can get: First, the system can detect the sound frequency emitted by the underwater sound source, and the standard deviation of the measurement of the 10 sonic frequencies around 7kHz is less than 8Hz. Second, the system detects the signal strength and underwater sound The source sound pressure level is exponential, and the minimum detection capability for the 3.5 kHz and 7 kHz sonic bands used for underwater target communication is 146.2 dB and 150.8 dB, respectively.