Brillouin optical fiber sensing system strain calibrating device and method

Abstract

The invention discloses a Brillouin optical fiber sensing system strain calibrating device and method. A ball screw is driven by a servo motor to rotate, a moving slider which is fixed to a guide railis made to do horizontal motion, and then single-mode bare optical fibers which are fixed to the moving slider are made to generate strain displacement; the optical fiber strain displacement is readthrough a grating ruler, and by comparing a reading value with a preset value, after the reading value reaches a deceleration range, a controller controls the servo motor to gradually slow down untilthe speed finally reaches the preset displacement value. It is achieved that the known constant strain is applied to the optical fibers, the amount of frequency shift of a Brillouin scattered light signal in the optical fibers is obtained by combining a Brillouin optical fiber sensing system, it is achieved that a strain-frequency shift coefficient is calibrated, and it also can be achieved that the strain parameter of the Brillouin optical fiber sensing system is calibrated. Compared with the prior art, the device is simple in structure and convenient to operate, and has the advantages of being high in positioning precision, parallelism and straightness, and low in backlash.

Description

technical field [0001] The invention relates to a calibration device and a calibration method suitable for a coal mine optical fiber sensing type safety monitoring system, in particular to a strain calibration device and a calibration method based on a Brillouin optical fiber sensing system. Background technique [0002] At present, optical fiber sensing technologies mainly include: Rayleigh scattering, Raman scattering and Brillouin scattering; Rayleigh scattering optical fiber sensing technology can only measure the loss and breakpoint of the optical fiber, but cannot measure physical quantities such as temperature and strain. Optical fiber sensing based on the principle of Mann scattering is one of the most mature technologies in distributed optical fiber sensing. The optical signal of Raman scattering is relatively weak, so it is difficult to detect, and it is only sensitive to temperature, so it is difficult to be used in applications that require stress detection. Geol...

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Problems solved by technology

[0004] The present invention aims at the inaccurate calculation of the strain-frequency shift coefficient caused by the inability to directly obtain the strain of the optical fiber in the prior art, thereby affecting the demodulation accuracy of the strain of the Brillouin optical fiber sensing system. The purpose of the present invention is to develop a set of The strain calibration device and calibration method of the Brillouin optical fiber sensing system, by applying a known standard strain to the optical fiber, combined with the Brillouin optical fiber sensing system to obtain the frequency shift of the Brillouin scattered light signal in the optical fiber, and then obtain the strain-frequency shift coefficient, and then realize the calibration of the strain parameter of the optical fiber sensing device

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