Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting

It is a basic task in Brillouin distributed fiber sensors to extract the peak frequency of the scattering spectrum, since the peak frequency shift gives information on the fiber temperature and strain changes. Because of high-level noise, quadratic fitting is often used in the data processing. Formu...

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Main Authors: Hanrong Zheng, Zujie Fang, Zhaoyong Wang, Bin Lu, Yulong Cao, Qing Ye, Ronghui Qu, Haiwen Cai
Format: Article
Language:English
Published: MDPI AG 2018-01-01
Series:Sensors
Subjects:
Online Access:http://www.mdpi.com/1424-8220/18/2/409
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author Hanrong Zheng
Zujie Fang
Zhaoyong Wang
Bin Lu
Yulong Cao
Qing Ye
Ronghui Qu
Haiwen Cai
author_facet Hanrong Zheng
Zujie Fang
Zhaoyong Wang
Bin Lu
Yulong Cao
Qing Ye
Ronghui Qu
Haiwen Cai
author_sort Hanrong Zheng
collection DOAJ
description It is a basic task in Brillouin distributed fiber sensors to extract the peak frequency of the scattering spectrum, since the peak frequency shift gives information on the fiber temperature and strain changes. Because of high-level noise, quadratic fitting is often used in the data processing. Formulas of the dependence of the minimum detectable Brillouin frequency shift (BFS) on the signal-to-noise ratio (SNR) and frequency step have been presented in publications, but in different expressions. A detailed deduction of new formulas of BFS variance and its average is given in this paper, showing especially their dependences on the data range used in fitting, including its length and its center respective to the real spectral peak. The theoretical analyses are experimentally verified. It is shown that the center of the data range has a direct impact on the accuracy of the extracted BFS. We propose and demonstrate an iterative fitting method to mitigate such effects and improve the accuracy of BFS measurement. The different expressions of BFS variances presented in previous papers are explained and discussed.
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spelling doaj.art-ff2f604df7d34c32893b4a384f4671ee2022-12-22T04:21:14ZengMDPI AGSensors1424-82202018-01-0118240910.3390/s18020409s18020409Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic FittingHanrong Zheng0Zujie Fang1Zhaoyong Wang2Bin Lu3Yulong Cao4Qing Ye5Ronghui Qu6Haiwen Cai7Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, ChinaShanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, ChinaShanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, ChinaShanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, ChinaNanjing Pioneer Lasersensing, Nanjing 210019, ChinaShanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, ChinaShanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, ChinaShanghai Key Laboratory of All Solid-State Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, ChinaIt is a basic task in Brillouin distributed fiber sensors to extract the peak frequency of the scattering spectrum, since the peak frequency shift gives information on the fiber temperature and strain changes. Because of high-level noise, quadratic fitting is often used in the data processing. Formulas of the dependence of the minimum detectable Brillouin frequency shift (BFS) on the signal-to-noise ratio (SNR) and frequency step have been presented in publications, but in different expressions. A detailed deduction of new formulas of BFS variance and its average is given in this paper, showing especially their dependences on the data range used in fitting, including its length and its center respective to the real spectral peak. The theoretical analyses are experimentally verified. It is shown that the center of the data range has a direct impact on the accuracy of the extracted BFS. We propose and demonstrate an iterative fitting method to mitigate such effects and improve the accuracy of BFS measurement. The different expressions of BFS variances presented in previous papers are explained and discussed.http://www.mdpi.com/1424-8220/18/2/409fiber optics sensorsoptical time domain reflectometryscatteringBrillouin
spellingShingle Hanrong Zheng
Zujie Fang
Zhaoyong Wang
Bin Lu
Yulong Cao
Qing Ye
Ronghui Qu
Haiwen Cai
Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting
Sensors
fiber optics sensors
optical time domain reflectometry
scattering
Brillouin
title Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting
title_full Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting
title_fullStr Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting
title_full_unstemmed Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting
title_short Brillouin Frequency Shift of Fiber Distributed Sensors Extracted from Noisy Signals by Quadratic Fitting
title_sort brillouin frequency shift of fiber distributed sensors extracted from noisy signals by quadratic fitting
topic fiber optics sensors
optical time domain reflectometry
scattering
Brillouin
url http://www.mdpi.com/1424-8220/18/2/409
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