Spectrum splicing optical frequency domain reflective distributed optical fiber sensor and signal demodulation method

Abstract

The invention discloses a spectrum splicing optical frequency domain reflective distributed optical fiber sensor and a signal demodulation method, comprising a narrow linewidth scanning laser, a first optical fiber coupler, an optical circulator, a sensing optical fiber, a polarization control unit, a second Fiber coupler, first polarization beam splitter, second polarization beam splitter, first balanced photodetector, second balanced photodetector, third fiber coupler, first Faraday rotation mirror, second Faraday rotation reflection mirror, reference fiber interferometer, photodetector, and signal acquisition and processing unit; by combining spectra, it avoids the use of lasers with a wide spectral range and no mode hopping, which reduces costs; simplifies laser packaging and control, which is conducive to miniaturized design; reduces It fulfills the requirements for ambient temperature and vibration conditions, which is conducive to engineering popularization and application.

Description

[0001] Technical field [0002] 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 [0003] 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. [0004] The time delay between the scattered or reflected signal light at different positions of the optical frequency domain reflective distributed optical fiber sensor and t...

AI Technical Summary

Problems solved by technology

[0006] 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

Images