Optical fiber Fabry-Perot sensor cavity length multi-frequency correlation demodulation method

A technology of Fap sensor and multi-frequency multiplication, which is applied in the direction of transmitting sensing components with optical devices, can solve the problems of inaccurate positioning of the peak value of the cross-correlation function, shorten the spectrum measurement range, reduce investment costs, and solve the barrier effect Effect

Active Publication Date: 2019-06-21
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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  • Optical fiber Fabry-Perot sensor cavity length multi-frequency correlation demodulation method
  • Optical fiber Fabry-Perot sensor cavity length multi-frequency correlation demodulation method
  • Optical fiber Fabry-Perot sensor cavity length multi-frequency correlation demodulation method

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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 optical fiber sensing technology field and especially relates to an optical fiber Fabry-Perot sensor cavity length multi-frequency correlation demodulation method. In theinvention, a problem that a difference between traditional cross-correlation function peak values is small so that judgment is fuzzy is solved. The method comprises the following steps of using broadband light emitted by a white light source to irradiate an optical fiber Fabry-Perot sensor, and collecting a reflection spectrum of the optical fiber Fabry-Perot sensor; carrying out cross-correlationoperation on a reflected spectral signal and a single frequency doubling template function to obtain a plurality of discrete peak values; then, carrying out cross-correlation operation on the reflected spectral signal and a multi-frequency doubling template function to extract an envelope of a multi-frequency doubling cross-correlation curve; and taking a wave trough position of an envelope curveas a reference, comparing with the plurality of discrete peak values obtained through single frequency doubling correlation, and taking a single frequency doubling signal peak value closest to the wave trough position of the envelope curve as a cavity length value of the corresponding optical fiber Fabry-Perot sensor. In the invention, demodulation precision of the optical fiber Fabry-Perot sensor is effectively improved.

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...

Claims

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Application Information

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Patent Type & Authority Applications(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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