应用于非本征光纤Fabry-Perot传感器的自适应FFT解调算法特性分析  

Characteristic Analysis of Adaptive FFT Demodulation Algorithm Applied to Extrinsic Fiber-Optic Fabry-Perot Sensors

作　　者：姚琼[1] 娄睿哲 谢志敏 刘政 夏霁 王付印 熊水东[1] 陈虎 Yao Qiong;Lou Ruizhe;Xie Zhimin;Liu Zheng;Xia Ji;Wang Fuyin;Xiong Shuidong;Chen Hu(College of Meteorology and Oceanography,National University of Defense Technology,Changsha 410073,Hunan,China;College of Underwater Acoustic Engineering,Harbin Engineering University,Harbin 150006,Heilongjiang,China;Naval Military Marine Environmental Construction Office,Beijing 100081,China)

机构地区：[1]国防科技大学气象海洋学院,湖南长沙410073 [2]哈尔滨工程大学水声工程学院,黑龙江哈尔滨150006 [3]海军军事海洋环境建设办公室,北京100081

出　　处：《光学学报》2024年第22期1-9,共9页Acta Optica Sinica

基　　金：国防科技基础加强计划(2019-JCJQ-ZD-026-00)。

摘　　要：提出一种基于白光干涉的自适应快速傅里叶变换(FFT)解调算法,用于非本征光纤Fabry-Perot(F-P)传感器的信号解调。通过自适应调整实际采集光谱的采样长度,自适应FFT解调算法能够精确计算反射光谱的本征频率,对传感器相位正交解调信号进行高效提取,实现高精度、低噪声、高稳定性的信号解调。从理论角度出发,分析所提出的解调算法与传统FFT算法对本征频率的估计精度,对两种解调算法的解调精度、解调稳定性、腔长适应范围以及复用阵列解调性能等进行仿真对比。结果表明,自适应FFT解调算法能够显著提高本征频率的计算精度,计算误差仅为10-4,为FFT解调算法的计算误差的1/10。同时,相对于传统FFT解调算法,自适应FFT算法的噪声谱级降低了约2 dB,且随腔长的变化仅有1 dB的波动,仅为传统算法波动幅度的1/3,且谐波失真降低了约20 dB,FFT在复杂噪声环境中的应用能力得到提升。此外,自适应FFT解调算法可高精度、稳定地解调任意腔长的非本征F-P传感器,并且具有分辨多基元叠加光谱本征频率的特点,相比FFT解调算法,串扰降低约20 dB,该算法可基于大规模复用非本征光纤F-P传感阵列进行信号解调。Objective Extrinsic fiber-optic Fabry-Perot(F-P)sensors measure external physical quantities by detecting changes in the interference spectra caused by cavity length variations or refractive index variations within the medium.Compared with traditional sensing technologies,F-P sensors are characterized by high sensitivity,small size,and immunity to electromagnetic interference,and widely employed in the measurement of a variety of external parameters such as pressure,temperature,vibration,displacement,acceleration,and gas.Fiber-optic sensing demodulation technology is an indispensable part of fiber optic sensing systems,which can influence the detection capability of a sensing system to a certain extent,and often needs to meet the requirements of high accuracy and fast calculation speed.Based on this,some demodulation algorithms introduce fast Fourier transform(FFT)as a fast spectrum analysis tool,but how to balance the demodulation accuracy and computational speed has become a major challenge.In our study,an adaptive FFT demodulation algorithm based on white light interference is proposed.Compared with the traditional FFT algorithm,this algorithm combines the efficient computational characteristics of the FFT algorithm and the idea of adaptive sampling length and realizes accurate eigenfrequency calculation by adjusting the spectral sampling length adaptively.Meanwhile,it performs the whole-cycle orthogonal phase-locked detection of spectra to realize accurate phase information extraction,which can improve the demodulation precision during the dynamic signal demodulation.During dynamic signal demodulation,on the one hand,the demodulation accuracy and stability can be improved,and on the other hand,the realtime spectrum refinement process required by the traditional FFT cavity length demodulation method under the dynamically changing cavity length can be avoided.Additionally,the phase demodulation accuracy can be significantly improved,with fast signal demodulation ensured.Methods White light interference technolo

关 键 词：白光干涉 相位解调 快速傅里叶变换 非本征光纤Fabry-Perot传感器 自适应性 

分 类 号：O436.1[机械工程—光学工程]