${\\pi}$ -Phase-Shifted FBG for High-Resolution Static-Strain Measurement Based on Wavelet Threshold Denoising Algorithm

Author

Wenzhu Huang ; Wentao Zhang ; Tengkun Zhen ; Fusheng Zhang ; Fang Li

Author_Institution

Optoelectron. Syst. Lab., Inst. of Semicond., Beijing, China

Volume

32

Issue

22

fYear

2014

fDate

Nov.15, 15 2014

Firstpage

4294

Lastpage

4300

Abstract

We propose a high-resolution static-strain sensor based on a π-phase-shifted Bragg grating (π-FBG) combined with a wavelet threshold denoising algorithm. The Pound-Drever-Hall (PDH) technique based on a narrow-linewidth fiber laser is used to interrogate the sensor. A reference FBG-based Fabry-Perot interferometer (FBG-FP) is used to compensate the temperature and laser source frequency fluctuation. As the reflect spectrums of π-FBG have a higher SNR than FBG-FP, the SNR of PDH signals from FBG-FP and π-FBG is increased from 18.1 to 35.6 dB. Wavelet threshold denoising algorithm is used to further improve the SNR of the PDH signals (about 8 dB). As a result, a static-strain resolution of 1.0 nε is obtained in the laboratory test.

Keywords

Bragg gratings; Fabry-Perot interferometers; compensation; fibre optic sensors; strain measurement; π-phase-shifted FBG; Pound-Drever-Hall technique; SNR; high-resolution static-strain measurement; laser source frequency fluctuation; narrow-linewidth fiber laser; reference FBG-based Fabry-Perot interferometer; static-strain resolution; temperature compensation; wavelet threshold denoising algorithm; Demodulation; Fiber gratings; Noise reduction; Sensors; Signal to noise ratio; Strain; ??-FBG; Pound???Drever???Hall (PDH) technique; static-strain sensor; wavelet threshold denoising;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/JLT.2014.2354413

Filename

6891109