Dual-channel high-precision temperature demodulation method based on distributed optical fiber Raman sensing system

Abstract

The invention belongs to the field of temperature demodulation in a distributed optical fiber sensing system, and discloses a two-way high-precision temperature demodulation method based on a distributed optical fiber Raman sensing system, comprising the following steps: S1, connecting device; S2, Calibration measurement stage: respectively collect the light intensity ratio of anti-Stokes light and Stokes light at each point in the reference fiber ring and any position L of the sensing fiber; S3, calibration measurement stage: collect calibration fiber ring The light intensity ratio of the backward anti-Stokes and Stokes light of the sensing fiber at different positions is calculated and linearly fitted to obtain all function values ​​of the temperature sensitivity factor of the sensing fiber with distance; S4, the measurement stage : collect the light intensity ratios of anti-Stokes light and Stokes light at each point in the reference fiber ring and at each position in the sensing fiber; S6, calculate and obtain all temperature information along the sensing fiber. The invention effectively solves the problem of low temperature measurement accuracy in the prior art, and can be widely used in distributed optical fiber sensing systems.

Description

technical field [0001] The invention belongs to the field of temperature demodulation in a distributed optical fiber sensing system, in particular to a high-precision Raman temperature demodulation method based on Stokes light demodulation anti-Stokes light. Background technique [0002] The distributed optical fiber Raman temperature measurement system has the advantages of anti-electromagnetic interference, anti-corrosion, electrical insulation, high sensitivity, good reliability, long service life, low cost, and good compatibility with ordinary optical fibers. Its temperature measurement principle is based on optical fiber Spontaneous Raman scattering and optical time-domain reflectometry localization techniques. The system injects high-power, narrow-pulse-width pulsed light waves into the multi-mode sensing fiber, and records the reflected back-spontaneous Raman backscattering light intensity at the same time, and then demodulates the temperature of each position along t...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem that the existing distributed optical fiber Raman sensing system has low temperature measurement accuracy and its technical bottleneck of being unable to change 1°C causes its application to be limited, the present invention proposes a distributed optical fiber Raman sensing system based on The dual-path high-precision temperature demodulation method, by introducing the fiber temperature sensitivity factor, recalibrates the Raman scattering signal intensity in the sensing fiber to improve the temperature sensitivity of its spontaneous Raman scattering to optimize the temperature accuracy of the system

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