High-precision optical fiber Raman temperature detection method based on anti-Stokes light self-demodulation

Abstract

The invention belongs to the field of temperature demodulation in a distributed optical fiber sensing system, and discloses a high-precision optical fiber Raman temperature detection method based on anti-Stokes light self-demodulation. The method comprises the following steps that S1, carrying out device construction; S2, a calibration and measurement stage: acquiring the light intensity of backward Raman scattering light of the anti-Stokes light of each point in a reference optical fiber ring and any position of a sensing optical fiber; S3, a calibration measurement stage: respectively collecting light intensity of backward Raman scattering light of the anti-Stokes light of a calibration optical fiber ring at different positions, and carrying out calculation and linear fitting to obtain all function values of temperature sensitive factors in the sensing optical fiber; S4, a measurement stage: collecting the light intensity of the backward Raman scattering light of the anti-Stokes light of each point in the reference optical fiber ring and each position in the sensing optical fiber; and S5, calculating to obtain all temperature information along the sensing optical fiber. The method effectively solves the problem of low temperature measurement precision of the distributed optical fiber Raman sensing system, and can be widely applied to the field of distributed optical fiber sensing.

Description

technical field [0001] The invention belongs to the field of temperature demodulation in distributed optical fiber sensing systems, in particular to a high-precision optical fiber Raman temperature detection method based on anti-Stokes light self-demodulation. Background technique [0002] The distributed optical fiber Raman temperature measurement system mainly relies on collecting the back Raman scattered light with temperature information generated when the pulsed light is transmitted in the optical fiber to demodulate the temperature information along the optical fiber, and then perform positioning according to the optical time domain reflection technology, thus Obtain temperature information at any position along the optical fiber. The back Raman scattered light used by the distributed Raman temperature measurement system to demodulate the temperature information has a very obvious temperature-sensitive effect in the silica fiber, and is not prone to nonlinear effects, ...

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 cannot break through the technical bottleneck of 1°C, which leads to its limited application, the present invention proposes a high-resolution sensor based on anti-Stokes light. The precision Raman temperature self-demodulation method introduces a temperature sensitivity factor into its Raman scattering signal to compensate the intensity of the spontaneous Raman scattering signal, thereby optimizing the temperature accuracy of the system

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