用傅里叶变换谱稳定法布里-珀罗型光纤水听器的工作点

Operating Point Stabilization of Fabry-Pérot Optical Fiber Hydrophone Based on Fourier Transform Spectrum

介绍了闭环反馈控制法稳定法布里-珀罗型光纤水听器相位工作点的基本原理,给出了法布里-珀罗型光纤水听器的声压相移灵敏度的表达式,推导了法布里-珀罗干涉透射光强替代函数的傅里叶变换解析式,用MathCAD软件绘制了该式对应的傅里叶变换谱线,通过谱线可以直观地了解系统输出信号的组成和特点。在实验中用频谱分析仪器记录了法布里-珀罗型光纤水听器透射光强的傅里叶变换谱,与软件仿真的理论谱线较好地吻合。通过实验进一步指出反馈临界点频率的选择方法,检验了反馈控制法在法布里-珀罗型光纤水听器相位工作点稳定过程中的实际效果,证明了该方法的可行性。

We introduce the fundamental of the phase operating point stabilization of Fabry-Pérot interference optical fiber hydrophone based on the loop-locked feedback control method, present the sound pressure phase-shift sensitivity expression of the Fabry-Pérot optical fiber hydrophone and deduce the Fourier transformation formula of transmission intensity substitution function of Fabry-Pérot interferometer. By MathCAD, we draw the Fourier transformation spectra of the above formula. Following the spectra, we can directly understand the composition and the characteristic of the system output signal. In experiments, the Fourier transformation spectral from transmission intensity of Fabry-Pérot optical fiber hydrophone is recorded by a spectral analysis instrument, which tallies well with the spectral drawn by MathCAD. Through the experiment, we further point out the choice method of the critical feedback point frequency, and examine the actual effect of the feedback control method in the stabilization of phase operating point process of Fabry-Pérot interference optical fiber hydrophone. The validity of the method is proved.