scholarly journals Absolute Single Cavity Length Interrogation of Fiber-Optic Compound Fabry–Perot Pressure Sensors Through a White Light Non-Scanning Correlation Method

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1628 ◽  
Author(s):  
Zilong Guo ◽  
Wentao Lv ◽  
Wei Wang ◽  
Qingqing Chen ◽  
Xiongxing Zhang ◽  
...  
Keyword(s):  
Fourier Transform ◽  
White Light ◽  
Cavity Length ◽  
Fiber Optic ◽  
Pressure Sensors ◽  
Correlation Method ◽  
Air Cavity ◽  
Basal Cavity ◽  
Fabry Perot ◽  
Absolute Length

A white light non-scanning correlation interrogation system was proposed and built to interrogate absolute length of the air cavity of fiber-optic compound Fabry–Perot pressure sensors for the extraction of pressure value. By carefully choosing thickness range and tilt angle of the optical wedge used for cavity length matching, correlation interferometric signal of the basal cavity can be naturally filtered out. Based on peak positioning by Fourier transform, bandpass filtering in frequency domain, inverse Fourier transform back to time domain, envelope fitting and zero fringe finding through a gravity center method, cavity length can be determined with an accuracy of 0.04%. The system was used for the interrogation of a fiber-optic compound Fabry–Perot pressure sensor under different pressures. For a pressure range of 0.1~2.9 Mpa, the linear relationship between the air cavity length and the gas pressure imposed was successfully extracted.

scholarly journals Two-Parameter Elliptical Fitting Method for Short-Cavity Fiber Fabry–Perot Sensor Interrogation

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 36 ◽  
Author(s):  
Xiongxing Zhang ◽  
Wei Wang ◽  
Haibin Chen ◽  
Ying Tang ◽  
Zhibo Ma ◽  
...  
Keyword(s):  
White Light ◽  
Cavity Length ◽  
Processing Method ◽  
Light Sources ◽  
Fitting Method ◽  
Data Processing Method ◽  
Fabry Perot ◽  
Gap Sensors ◽  
Two Parameter ◽  
Better Than

To solve the cavity interrogation problem of short cavity fiber Fabry–Perot sensors in white light spectral interrogation with amplified spontaneous emissions (ASEs) as the white light sources, a data processing method, using an improved elliptical fitting equation with only two undetermined coefficients, is proposed. Based on the method, the cavity length of a fiber Fabry–Perot sensor without a complete reflection spectrum period in the frequency domain can be interrogated with relatively high resolution. Extrinsic fiber Fabry–Perot air-gap sensors with cavity lengths less than 30 μm are used to experimentally verify the method, and are successfully interrogated with an accuracy better than 0.55%.

Embedded micromachined fiber-optic fabry-perot pressure sensors in aerodynamics applications

2003 ◽  
Vol 3 (1) ◽  
pp. 102-107 ◽  
Author(s):  
M.J. Gander ◽  
W.N. MacPherson ◽  
J.S. Barton ◽  
R.L. Reuben ◽  
J.D.C. Jones ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Pressure Sensors ◽  
Fabry Perot

Fiber-Optic Extrinsic Fabry-Perot Interferometer Sensors with Multi-Wavelength Intensity Demodulation

2013 ◽  
Vol 470 ◽  
pp. 630-635 ◽  
Author(s):  
Ning Fang Song ◽  
Rui Qi Cui ◽  
Yu Jie Yang ◽  
Xiao Liang Xu
Keyword(s):  
Incident Wave ◽  
High Speed ◽  
Cavity Length ◽  
Fiber Optic ◽  
Wave Length ◽  
Fabry Perot ◽  
Multiple Wavelengths ◽  
Large Scope ◽  
Multi Wavelength ◽  
Novel Method

In this paper, a novel method used for Fabry-Perot cavity length's demodulation in high-speed and large scope measurement was proposed. Principle of the method is based on uniqueness of intensity of multiple wavelengths in the scope of Fabry-Perot vibration. This technique offers flexibility of selecting incident wave length and enhances the scope of demodulation of cavity length, compared with that popular triple wave length demodulation. In experiment, multi-wavelength demodulation is demonstrated for measurement of cavity length varying from 110um to 115um and the strain resolution was higher than 0.1um.

scholarly journals A High-Speed Demodulation Technology of Fiber Optic Extrinsic Fabry-Perot Interferometric Sensor Based on Coarse Spectrum

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6609
Author(s):  
Peng Zhang ◽  
Ying Wang ◽  
Yuru Chen ◽  
Xiaohua Lei ◽  
Yi Qi ◽  
...  
Keyword(s):  
Real Time ◽  
High Speed ◽  
Cavity Length ◽  
Fiber Optic ◽  
Likelihood Estimation ◽  
Time Dynamic ◽  
Wavelength Division ◽  
Broadband Spectrum ◽  
Fabry Perot ◽  
Interferometric Sensor

A fast real-time demodulation method based on the coarsely sampled spectrum is proposed for transient signals of fiber optic extrinsic Fabry-Perot interferometers (EFPI) sensors. The feasibility of phase demodulation using a coarse spectrum is theoretically analyzed. Based on the coarse spectrum, fast Fourier transform (FFT) algorithm is used to roughly estimate the cavity length. According to the rough estimation, the maximum likelihood estimation (MLE) algorithm is applied to calculate the cavity length accurately. The dense wavelength division multiplexer (DWDM) is used to split the broadband spectrum into the coarse spectrum, and the high-speed synchronous ADC collects the spectrum. The experimental results show that the system can achieve a real-time dynamic demodulation speed of 50 kHz, a static measurement root mean square error (RMSE) of 0.184 nm, and a maximum absolute and relative error distribution of 15 nm and 0.005% of the measurement cavity length compared with optical spectrum analyzers (OSA).

scholarly journals A Zero-Cross Detection Algorithm for Cavity-Length Interrogation of Fiber-Optic Fabry–Perot Sensors

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3868
Author(s):  
Ma ◽  
Song ◽  
Huang ◽  
Guo ◽  
Yuan ◽  
...  
Keyword(s):  
Power Density ◽  
Cavity Length ◽  
Fiber Optic ◽  
Spectral Power ◽  
Spectral Power Density ◽  
Maximum Error ◽  
Detection Algorithm ◽  
Slow Variation ◽  
Fabry Perot ◽  
And Performance

A zero-cross detection algorithm was proposed for the cavity-length interrogation of fiber-optic Fabry–Perot (FP) sensors. The method can avoid the inaccuracy of peak determination in the conventional peak-to-peak method for the cavity-length interrogation of fiber-optic FP sensors caused by the slow variation of the spectral power density in peak neighboring regions. Both simulations and experiments were carried out to investigate the feasibility and performance of the zero-cross detection algorithm. Fiber-optic FP sensors with cavity lengths in the range of 150–1000 μm were successfully interrogated with a maximum error of 0.083 μm.

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