干涉型光纤水听器3×3反正切解调方法

Research on 3×3 arctangent demodulation method for interferometric fiber hydrophone

光纤水听器具有体积小、灵敏度高、传输损耗低、抗电磁干扰能力强等优点,这些优点极大地促进了其在海防领域的发展。为了实现耦合器相位特性不理想条件下的无失真解调,本文提出一种基于3×3光纤耦合器的反正切解调方法。首先推导出解调输出信号的表达式,给出解调频率范围。然后建立干涉型光纤水听器信号解调算法Simulink模型,并利用正切函数的性质,实现反正切相位扩展。在单频信号和线性调频信号条件下进行了仿真。仿真结果表明,该方法具有较宽的频率解调范围,消除了3×3耦合器的输出相位差对解调的影响。搭建基于此算法的干涉型光纤水听器解调系统,对实验数据进行了分析。结果证明了该方法的可行性和实用性,对干涉型光纤水听器的数字化解调系统设计具有一定的理论指导价值。

Fiber optic hydrophone has the advantages of small size,high sensitivity,low transmission loss and strong anti-electromagnetic interference ability,which greatly promotes its development in coastal defense field.In order to realize the demodulation without distortion under the condition that the phase characteristic of the fiber coupler is not ideal.In this paper,an anti-tangent demodulation method based on 3×3 optical fiber coupler is proposed.Firstly,the paper deduced the expression of the output signal and gave the range of the frequency.Then established the simulation model of signal demodulation system for interferometric fiber optic hydrophone and realized the arc-tangent phase expansion based on the properties of tangent function.The simulation is carried out under the condition of single frequency signal and linear frequency modulation signal.The simulation results demonstrated that This method has a wide demodulation frequency range and eliminated the influence of the output phase difference of the 3×3 coupler on the demodulation result.Finally,an interferometric fiber optic hydrophone demodulation system based on this algorithm is built.The experimental data are obtained,and the analysis results prove the feasibility and practicability of the method.The research has certain theoretical guidance value for the design of digital demodulation system of interferometric fiber optic hydrophone.