光纤法布里-珀罗传感器串连复用的傅里叶变换解调方法初探

光纤法布里—珀罗传感器复用、特别是串连复用的解调十分困难。为解决这个问题，从光纤法布里—珀罗应变传感器的基本原理出发、在仅有两只传感器复用的基本条件下，深人分析了复用系统组合输出光强信号及其分布特性；研究了对其进行傅里叶变换的解调原理及具体实现方法，分析了因复用信号不满足傅里叶变换条件而在变换域产生的畸变，进行了计算机仿真解调。在此基础上，搭建了两只传感器的串连复用实验系统，并用此方法实现了两只复用传感器的解调，且传感器之间的相互影响小于5％。理论与实验表明，虽然传感器的复用信号不满足傅里叶变换的标准条件，且仿真与实验存在一定差异，但所提出的傅里叶变换方法，基本可用于光纤法布里—珀罗传感器的串连复用解调。

Study on the Serial Multiplex of Optical Fiber Fabry-Perot Strain Sensors with Fourier Transform

It is very difficult to multiplex fiber Fabry-Perot sensor because of its fundamental limitation. When serially multiplexed, it is especially complicated due to mutual affection between sensors. To address this problem, the simplest case of two fiber Fabry-Perot (F-P) sensors multiplexed in series was discussed. According to the principle of double beam interference, the output of serially multiplexed sensors was derived, and its characteristics was discussed in detail. Fourier transform was adopted to transform the output from wavelength domain into spatial frequency domain. The dissatisfaction of conditions for using Fourier transform signal processing of fiber Fabry-Perot senor was discussed, and distortion of Fourier transform was analyzed. With the simulation of Fourier transform, the eigenvalues of two fiber Fabry-Perot sensor were demultiplexed in spatial frequency domain. In addition, experiment of serial multiplexing two fiber Fabry-Perot sensors was carried out. The experimental results showed that, Fourier transformation in demultiplexing serially multiplexed fiber Fabry-Perot sensors was valid, and mutual affection between two fiber Fabry-Perot sensors was less than 5%.