A Cavity Length Multiple Frequency Correlation Demodulation Method for Fiber Optic FAP Sensors

A Fa-Per sensor, multi-frequency technology, applied in the direction of using optical devices to transmit sensing components, can solve the problems of inaccurate peak positioning of the cross-correlation function, shorten the spectral measurement range, improve the accuracy, and solve the effect of the fence effect.

Active Publication Date: 2021-04-06
XIAN TECH UNIV
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Problems solved by technology

[0005] Aiming at the inaccurate positioning of the peak value of the cross-correlation function by the existing correlation method demodulation method, the present invention proposes a cavity length multi-frequency correlation demodulation method for optical fiber F-P sensor

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  • A Cavity Length Multiple Frequency Correlation Demodulation Method for Fiber Optic FAP Sensors
  • A Cavity Length Multiple Frequency Correlation Demodulation Method for Fiber Optic FAP Sensors
  • A Cavity Length Multiple Frequency Correlation Demodulation Method for Fiber Optic FAP Sensors

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Embodiment

[0035] A cavity length multiple frequency multiplication correlation demodulation method of an optical fiber F-P sensor, the specific steps are as follows:

[0036] Step 1: Collect the reflection spectrum signal of the fiber optic FAPO sensor: the spectrometer collects the reflection spectrum signal of the fiber optic FAPO sensor, and changes the spectral signal coordinate from wavelength λ to frequency v, and the spectral signal is recorded as Y(v);

[0037] Step 2: Single-octave cross-correlation calculation: combine the measured reflection spectrum signal Y(v) with the template function C 0 (v) Do related operations, the template function takes Thus, the single-octave cross-correlation function expression is obtained as:

[0038]

[0039] The related operation results are as Figure 4 As shown, it can be seen that the envelope peak of the cross-correlation function spectrum tends to be flat between 75 μm and 85 μm, and the cavity length value of the single-octave cros...

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Abstract

The invention belongs to the technical field of optical fiber sensing, and in particular relates to a cavity length-multiple-frequency correlation demodulation method of an optical fiber F-P sensor. The present invention aims to solve the problem of fuzzy judgment due to the small difference between the peak values ​​of the traditional cross-correlation function. The cross-correlation operation is performed on the spectral signal and the single-octave template function to obtain multiple discrete peaks, and then the cross-correlation operation is performed on the reflected spectral signal and the multi-octave template function to extract the envelope of the multi-octave cross-correlation curve, and the envelope The trough position of the curve is used as a reference, compared with multiple discrete peaks obtained by single-octave correlation, and the single-octave signal peak closest to the trough position of the envelope curve is taken as the cavity length value of the corresponding fiber optic sensor. The invention effectively improves the demodulation precision of the optical fiber FAP sensor.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a cavity length-multiple-frequency correlation demodulation method of an optical fiber F-P sensor. Background technique [0002] The optical fiber F-P cavity sensor has the advantages of small size, light weight, high sensitivity, large dynamic response range and anti-electromagnetic interference. It is used in different fields such as aerospace, bridges, oil fields, dams, etc. [0003] The key to the application of the fiber optic FAP sensor is the demodulation of the sensor FAP cavity length. The most typical demodulation method is phase demodulation. The phase demodulation method is mainly divided into peak pursuit method, Fourier transform method and cross-correlation method. The peak tracking method determines the cavity length by locating the relative change of the peak position in the spectrum. The single-peak method is suitable for the relativ...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01D5/353
Inventor 张雄星张瑶王伟陈海滨郭子龙高明王可宁陈阳
Owner XIAN TECH UNIV
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