Distributed fiber temperature strain sensing system and method based on Brillouin scattering

A Brillouin scattering, distributed optical fiber technology, applied in thermometers with physical/chemical changes, thermometers, and force measurement by measuring changes in optical properties of materials when they are stressed, which can solve complex installation, temperature and strain. The problems of high demodulation cost and weak detection signal can simplify the test system and eliminate the disturbance of the optical path.
CN107436201APending Publication Date: 2017-12-05SHANDONG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
SHANDONG UNIV
Publication Date
2017-12-05

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Abstract

The invention discloses a distributed fiber temperature strain sensing system and method based on Brillouin scattering. A distributed feedback laser is adopted to emit continuous light with a narrow linewidth, the light is externally modulated by a photoelectric modulator into pulse light, an erbium doped fiber amplifier is adopted to amplify the pulse light, and then the amplified pulse light enters, as incident light, a sensing fiber so that a Brillouin backward signal in the fiber is obtained. The Brillouin scattering signal is obtained through a single-end input way, so it is convenient to install and use the system. Homologous heterodyne interferometry is adopted to demodulate the signal, thereby avoiding requirements of general interferometry for similarity of luminous intensity of two light beams and simplifying a testing system. Certain measures are taken to enhance the signal, so subsequent processing can be conducted. Meanwhile, changes of Brillouin frequency shift and intensity are obtained through application of an electric method, temperature and strain are demodulated, and temperature and strain are measured at the same time.
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Description

technical field

[0001] The invention relates to the field of distributed optical fiber sensing, in particular to a distributed optical fiber temperature and strain sensing system and method based on Brillouin scattering. Background technique

[0002] A distributed optical fiber sensing system can be defined as an instrument or system that can sense the change of the measured parameter with the direction of the fiber length in the form of a continuous function of distance on a continuous fiber length. The distributed temperature and stress sensing system usually arranges the optical fiber along the temperature field and the stress field, and measures the scattered light carrying temperature and stress information generated when the light is transmitted in the optical fiber. Domain Reflectometer) technology can measure and monitor the temperature, stress spatial distribution and time-varying information along the optical fiber transmission path.

[0003] The research on distr...

Claims

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