A High-Resolution Demodulation Algorithm for FBG-FP Static-Strain Sensors Based on the Hilbert Transform and Cross Third-Order Cumulant

Static strain can be detected by measuring a cross-correlation of reflection spectra from two fiber Bragg gratings (FBGs). However, the static-strain measurement resolution is limited by the dominant Gaussian noise source when using this traditional method. This paper presents a novel static-strain...

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Bibliographic Details
Published in:Sensors (Basel, Switzerland) Switzerland), 2015-04, Vol.15 (5), p.9928-9941
Main Authors: Huang, Wenzhu, Zhen, Tengkun, Zhang, Wentao, Zhang, Fusheng, Li, Fang
Format: Article
Language:English
Subjects:
Algorithms
Correlation analysis
cross third-order cumulant
Demodulation
demodulation algorithm
FBG-based Fabry-Perot interferometers
Gaussian
high resolution
Hilbert transform
Lasers
Noise
Random vibration
Reflection
Sensors
Spectra
static strain
Transforms
Wavelet transforms
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Summary:Static strain can be detected by measuring a cross-correlation of reflection spectra from two fiber Bragg gratings (FBGs). However, the static-strain measurement resolution is limited by the dominant Gaussian noise source when using this traditional method. This paper presents a novel static-strain demodulation algorithm for FBG-based Fabry-Perot interferometers (FBG-FPs). The Hilbert transform is proposed for changing the Gaussian distribution of the two FBG-FPs' reflection spectra, and a cross third-order cumulant is used to use the results of the Hilbert transform and get a group of noise-vanished signals which can be used to accurately calculate the wavelength difference of the two FBG-FPs. The benefit by these processes is that Gaussian noise in the spectra can be suppressed completely in theory and a higher resolution can be reached. In order to verify the precision and flexibility of this algorithm, a detailed theory model and a simulation analysis are given, and an experiment is implemented. As a result, a static-strain resolution of 0.9 nε under laboratory environment condition is achieved, showing a higher resolution than the traditional cross-correlation method.
ISSN:1424-8220
1424-8220
DOI:10.3390/s150509928