Method used for measuring temperature and strain simultaneously and based on brillouin scattering

Abstract

A method used for measuring temperature and strain simultaneously and based on brillouin scattering adopts one measuring system. The measuring system comprises a narrow linewidth laser, a polarization-maintaining coupler, an optical coupler, an optical modulator, an optical amplifier, a circulator, a photoelectric detector and a brillouin frequency shift and strength testing unit. A first optical port of the polarization-maintaining coupler is connected with the laser. A third optical port of the polarization-maintaining coupler is connected with a first optical port of the circulator through the optical modulator and the optical amplifier sequentially. A second optical port of the circulator is connected with sensor fiber, a third optical port of the circulator is connected with a first optical port of the optical coupler, a fourth optical port of the polarization-maintaining coupler is connected with a second optical port of the optical coupler, and a third optical port of the optical coupler is connected with the brillouin frequency shift and strength testing unit through the photoelectric detector. Under the premise that system measuring precision is not reduced, resolution ratio of a measuring space is improved, simultaneously signal to noise ratio of the system can be improved, sensing distance is increased, and measuring time is reduced.

Description

technical field [0001] The invention relates to a method for simultaneously measuring temperature and strain by using a Brillouin optical time domain reflection system, which belongs to the field of measurement technology. Background technique [0002] Brillouin distributed optical fiber temperature and strain simultaneous measurement technology has the unique advantages of obtaining distribution information along the entire optical fiber measured field with only one measurement, high measurement accuracy, accurate positioning, and a distance of tens of kilometers. It has broad application prospects in online monitoring of the health status of large-scale engineering structures in industries such as construction, water conservancy, and fault location. The Brillouin Optical Time Domain Reflectometer (BOTDR) is a fully distributed optical fiber sensing system based on Brillouin scattering, which uses the frequency of Brillouin backscattered light in the sensing fiber The line...

AI Technical Summary

Problems solved by technology

Although the method overcomes the contradiction between the spatial resolution of the system and the measurement accuracy, it cannot realize the simultaneous measurement of temperature and strain, and cannot effectively improve the signal-to-noise ratio of the system, which limits the sensing distance of the entire system

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