Brillouin time domain analysis system and method based on multi-core optical fiber

Abstract

The invention provides a Brillouin time domain analysis system and method based on a multi-core optical fiber. According to the analysis system and method, a pulsed chaotic laser signal source is setto generate a chaotic optical signal with good characteristics, high-resolution measurement irrelevant to distance can be realized, and position information of a maintenance fault point of the opticalfiber can be accurately reflected. In order to eliminate the problem that Brillouin frequency shifts are sensitive to bending in eccentric fiber cores, according to the embodiment, the Brillouin frequency shifts of two symmetrical outer cores are averaged first, so that the effect of bending on the Brillouin frequency shifts is eliminated; and then the averaged Brillouin frequency shifts and dataof the middle core are combined to solve a coefficient matrix, so that decoupling of temperature and stress is realized.

Description

technical field [0001] The invention relates to the field of distributed optical fiber sensing, in particular to a multi-core optical fiber-based Brillouin time-domain analysis system and method. Background technique [0002] With the rapid development of optical fiber sensing technology, more and more people pay attention to optical fiber sensing technology, and it is gradually becoming another major optical fiber application technology industry after the optical fiber communication industry. According to our existing research results, it is found that the Brillouin frequency shift of the outer core of the multi-core fiber is sensitive to bending, while the middle core is not sensitive to bending like the ordinary single-mode fiber, so the construction of multi-core fiber The Brillouin distributed sensing system can not only measure temperature and longitudinal stress, but also measure transverse bending, which is equivalent to expanding a dimension. However, experiments h...

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Problems solved by technology

However, experiments have found that in multi-core fibers, the Brillouin gain peaks at different positions of the intermediate core appear at relatively consistent frequency shifts, while the Brillouin frequency shifts at different positions in eccentric cores show obvious differences. After analysis, it is believed that the random fluctuation of the Brillouin frequency shift of the outer core in the multi-core fiber is caused by bending, and the total amount of Brillouin frequency shift in the multi-core fiber is caused by bending. There is a large difference from the theoretical value, which makes the positioning result inaccurate. Therefore, in order to solve the above problems, the present invention provides a Brillouin time-domain analysis system and method based on multi-core optical fiber, which can eliminate the Brillouin time domain analysis system and method caused by bending. Deep frequency shift, and space division multiplexing can be realized

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