1results about How to "Sensitive to temperature changes" patented technology

This invention relates to the field of marine environmental monitoring technology, and discloses a temperature, salinity, and depth sensing system and demodulation method based on a polarization-maintaining fiber optic π-phase-shifting grating. The system includes a polarization-maintaining fiber and a π-phase-shifting fiber grating, with the π-phase-shifting fiber grating inscribed on the polarization-maintaining fiber and serving as a single sensing unit. The reflection spectrum of the sensing unit contains reflection peaks along both the fast and slow axes, with an ultra-narrow linewidth transmission window introduced by the π-phase shift at the center of each peak. A salinity-sensitive thin film is coated on the π-phase-shifting region of the sensing unit, covering the π-phase-shifting region and extending into a local area of ​​the π-phase-shifting fiber grating, but not covering the entire grating. By locally coating the salinity-sensitive thin film on the π-phase-shifting region of a single polarization-maintaining fiber optic π-phase-shifting grating, and simultaneously extracting the characteristic wavelength changes of its fast and slow axis reflection center wavelengths and transmission window wavelengths, a sensitivity matrix is ​​used to achieve synchronous decoupled measurement of the three parameters of temperature, salinity, and depth.