US 11,965,821 B1
Optical fiber sensing system for temperature and salinity synchronous measurement
Xiaoguang Mu, Zhanjiang (CN); Lin Sun, Zhanjiang (CN); Yuying Zhang, Zhanjiang (CN); Yuting Li, Zhanjiang (CN); Kun Song, Zhanjiang (CN); Jiale Gao, Zhanjiang (CN); and Yuqiang Yang, Zhanjiang (CN)
Assigned to Guangdong Ocean University, Zhanjiang (CN)
Filed by GUANGDONG OCEAN UNIVERSITY, Guangdong (CN)
Filed on Aug. 26, 2023, as Appl. No. 18/456,486.
Application 18/456,486 is a continuation of application No. PCT/CN2023/104776, filed on Jun. 30, 2023.
Claims priority of application No. 202310383311.X (CN), filed on Apr. 12, 2023.
Int. Cl. G01N 21/17 (2006.01); G01J 5/0821 (2022.01)
CPC G01N 21/17 (2013.01) [G01J 5/0821 (2013.01); G01N 2021/1734 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An optical fiber sensing system for temperature and salinity synchronous measurement, comprising a broad-spectrum light source, an optical fiber circulator, a coupler, a first interferometer, a second interferometer, a third interferometer and a spectrometer;
wherein the first interferometer is connected in series with the optical fiber circulator and the coupler in sequence; the coupler is respectively connected with the second interferometer, the third interferometer and the spectrometer; the second interferometer is connected in parallel with the third interferometer;
the first interferometer is insensitive to the temperature and the salinity; the second interferometer is sensitive to both the temperature and the salinity, and the third interferometer is only sensitive to the temperature;
light emitted by the broad-spectrum light source passes through the optical fiber circulator and enters the first interferometer; reflected light of the first interferometer passes through the optical fiber circulator and the coupler in sequence, and then enters the second interferometer and the third interferometer respectively; reflected light of the second interferometer and the third interferometer enters the spectrometer after passing through the coupler; and the temperature to be measured and the salinity to be measured are simultaneously obtained by performing a spectral analysis of the reflected light entering the spectrometer;
the spectral analysis of the reflected light entering the spectrometer comprises:
respectively obtaining interference spectra of the first interferometer, the second interferometer and the third interferometer based on the reflected light entering the spectrometer;
obtaining a first interference spectra envelope between the first interferometer and the second interferometer based on the interference spectrum of the first interferometer and the interference spectrum of the second interferometer; obtaining a second interference spectra envelope between the first interferometer and the third interferometer based on the interference spectrum of the first interferometer and the interference spectrum of the third interferometer; and
obtaining the temperature to be measured and the salinity to be measured based on the first interference spectra envelope and the second interference spectra envelope; and
obtaining the temperature and the salinity comprises:
obtaining a first translation amount of the first interference spectra envelope and a second translation amount of the second interference spectra envelope when the temperature and the salinity change; and
obtaining the temperature to be measured and the salinity to be measured based on the first translation amount and the second translation amount.