Distributed sensing method and system based on Brillouin scattering and chaotic optical signals

Abstract

A distributed sensing system based on Brillouin scattering and chaotic optical signals includes a laser module (1), a first circulator (2), a first coupler (3), an optical switch (4), a chaotic laser signal generation control module (5), a first optical isolator (6), a second coupler (7), a first polarization controller (8), a first electro-optic modulator (9), a first optical amplifier (10), a second polarization controller (11), a second electro-optic modulator (12), an electrical signal modulation module (13), a bias voltage control module (14), a tunable optical delay line, a second optical amplifier, a scrambler (17), a second optical isolator, an optical fiber to be measured, a second circulator, a tunable optical filter, a photoelectric detection module, and a data acquisition and processing module. A Brillouin correlation analysis sensing system based on Brillouin scattering distributed optical time-domain analysis sensing and chaotic optical signals is realized, and a target can be located quickly and with high precision.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, and relates to a distributed optical fiber sensing method and system, in particular to a distributed strain and temperature sensing monitoring method and system based on Brillouin scattering and fusion of chaotic optical signals. Background technique [0002] Studies have shown that there is a linear relationship between strain or temperature and the Brillouin frequency shift. In 1989, Horiguchi et al. proposed the Brillouin Optical Time-Domain Analysis (BOTDA) sensing technology based on the stimulated Brillouin scattering amplification effect, also known as Brillouin gain type BOTDA. In the Brillouin gain BOTDA sensing technology, the two ends of the optical fiber are respectively injected with pulsed light as pump and continuous light as detection, and the frequency difference of the two paths of light is about one Brillouin frequency shift. The Brillouin scattering effect, the ...

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Problems solved by technology

[0004] Both of the above two technologies measure the temperature and strain by measuring the Brillouin frequency shift in the optical fiber. The main difference is that the BOTDA technology does not need to adjust the delay line and can directly obtain the position of the frequency shift point. The disadvantage lies in the spatial resolution The rate is limited by the width of the pump pulse; the CHAOS-BOCDA technology obtains high spatial resolution through the coherence length of the chaotic optical signal, and the resolution is as high as cm. , it needs to be obtained by changing the length of the delay line point by point. When the sensing distance is long, this measure of changing the length of the delay line reduces the test efficiency of the system and is difficult to meet the needs of practical engineering applications.

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