Spectrum splicing optical frequency domain reflection-type distributed fiber sensor and signal demodulation method

Abstract

The present invention discloses a spectrum splicing optical frequency domain reflection-type distributed fiber sensor and a signal demodulation method. The spectrum splicing optical frequency domain reflection-type distributed fiber sensor comprises a narrow linewidth scanning laser, a first optical fiber coupler, an optical circulator, a sensing optical fiber, a polarization control unit, a second optical fiber coupler, a first polarization beam splitter, a second polarization beam splitter, a first balance photoelectric detector, a second balance photoelectric detector, a third optical fibercoupler, a first Faraday rotation reflector, a second Faraday rotation reflector, a reference fiber optic interferometer, a photoelectric detector and a signal collection processing unit. Through spectrum splicing, it is avoided that a laser with a broadband spectrum range and without mode jump is employed to reduce the cost; the laser package and control are simplified to facilitate miniaturization design; and the requirements for the environment temperature and the vibration condition are reduced to facilitate project promotion application.

Description

Technical field [0001] The invention relates to a distributed optical fiber sensor, in particular to a spectral splicing optical frequency domain reflective distributed optical fiber sensor. Background technique [0002] Optical frequency domain reflective distributed optical fiber sensor, through the optical frequency domain reflectometer to measure the backward Rayleigh scattering along the optical fiber and the backward reflection of the fiber grating, can realize distributed measurement or multi-point measurement of optical fiber temperature, strain, vibration, etc. , has the advantages of high spatial resolution, large number of measuring points, and low average cost of a single measuring point, and is widely used in structural monitoring such as aerospace, aviation, and civil engineering. [0003] The time delay between the scattered or reflected signal light at different positions of the optical frequency domain reflective distributed optical fiber sensor and the loca...

AI Technical Summary

Problems solved by technology

[0005] The technical problem solved by the present invention is: the existing optical frequency domain reflective distributed optical fiber sensor needs to use a narrow linewidth scanning laser without mode hopping in the measurement spectrum range, which has high cost, large volume, narrow working temperature range and vibration reduction. Requires high-level problems; a spectral mosaic optical frequency domain reflective distributed optical fiber sensor and signal demodulation method is proposed, the measured spectral range is divided into N (N ≥ 2) spectral intervals, and the wavelength of the narrow linewidth scanning laser is sequentially Non-mode-hopping wavelength scanning is carried out in N spectral intervals, and the scattered or reflected signal light spectra in each spectral interval are spliced ​​through digital signal processing to obtain the signal optical spectrum within the measured spectral range, and the optical frequency domain reflective distribution is completed Signal demodulation of optical fiber sensor; reduces the requirements of optical frequency domain reflective distributed optical fiber sensor for laser, reduces cost and volume, improves environmental adaptability, and is conducive to engineering promotion and application

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