Distributed sensing system and method for simultaneously measuring fiber bragg grating vibration and strain

Abstract

The invention discloses a distributed sensing system and method for simultaneously measuring fiber bragg grating vibration and strain. The distributed sensing system comprises a low-coherence broadband light source; a fiber grating sensor; a double-path time delay optical fiber structure which takes the low-coherence broadband light source as input and outputs double-path low-coherence continuouslight to the optical fiber grating sensor, two paths of low-coherence reflection signals are output by taking the separated light signals reflected by the fiber bragg grating sensor as input; a photoelectric detector array which is used for detecting the two paths of low-coherence reflection signals and obtaining corresponding information of external vibration signals by analyzing phase and intensity changes of interference; and a wavelength demodulation unit which is used for detecting the wavelength change of the separated optical signal reflected by the fiber bragg grating sensor to realizestrain sensing. The invention has the advantages that the method can be directly used or fused in the existing fiber bragg grating array system, the signal-to-noise ratio and sensitivity of the system are high, the frequency detection range is large, and the distributed simultaneous measurement of vibration and strain can be realized.

Description

technical field [0001] The invention relates to a high signal-to-noise ratio and high-sensitivity low-coherence fiber grating array vibration sensing and strain sensing system and method, which are used for distributed sensing in aerospace, civil engineering traffic structures, geotechnical, well logging, and seismic exploration. Sensing of vibration, sound waves and strain. Background technique [0002] Distributed monitoring of distributed vibration, sound waves and strains is critical and widely required in civil engineering, transportation structures, geotechnical, well logging, and seismic exploration projects. As an emerging distributed sensing technology in recent years, fiber optic sensing has great application potential for the above engineering requirements. At present, the technologies that can be used for structural distributed strain and vibration sensing mainly include fiber grating sensing, back Rayleigh scattering or Weak grating array technology method. Am...

AI Technical Summary

Problems solved by technology

However, most of the existing practical technical systems have single functions, complex systems, high costs, and low performance, and it is difficult to meet the multi-parameter, low-cost, and high-performance distributed monitoring of the target to be measured.

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