Distributed fiber sensing method and device for simultaneously measuring temperature and strain

Abstract

The invention belongs to the distributed fiber sensing technology, and provides a distributed fiber sensing method and a distributed fiber sensing device for simultaneously measuring temperature and strain. The method comprises the following steps of: calibrating Brillouin frequency shift temperature coefficients and strain coefficients of a sensing fiber to be measured, which correspond to incident light of two different wavelengths; measuring the Brillouin frequency shift quantity of the sensing fiber in the two different wavelengths; and calculating the temperature and strain distribution of the sensing fiber. Specifically, the incident light of the two different wavelengths can be sequentially and separately injected into the sensing fiber during measurement, and can also be simultaneously injected into the sensing fiber through a wavelength division multiplexer. By adopting the common single mode fiber, the cost is low and long-distance distributed sensing can be realized; and only the Brillouin frequency shift quantity in different pumping wavelengths is required to be measured, so that the measurement precision is effectively improved, and the structure of the system is relatively simple.

Description

technical field [0001] The invention belongs to distributed optical fiber sensing technology, in particular to a distributed optical fiber sensing technology based on Brillouin scattering based on dual-wavelength simultaneous measurement of temperature and strain. Background technique [0002] Distributed optical fiber sensors use the optical fiber itself as both the sensing body and the transmission medium, and can accurately measure information such as stress, temperature, vibration, and damage at any point along the optical fiber, and can easily realize long-distance, distributed monitoring. If the optical fibers are criss-crossed into a network, a monitoring network with a certain scale can be formed to realize all-round detection of monitoring objects, overcome the disadvantages of missed detection by traditional point detection, and improve the success rate of detection. Based on the outstanding characteristics of distributed optical fiber sensors, it has other sensing...

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Problems solved by technology

[0007] The problem to be solved by the present invention is that in ordinary single-mode optical fiber, only the Brillouin frequency shift is used to realize the simultaneous sensing of temperature and strain, neither need to test the Brillouin scattered light power, nor need expensive special optical fiber, and at the same time only based on Brillouin scattering

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