Dynamic distributed Brillouin optical fiber sensing device and method

Abstract

The invention discloses a dynamic distributed Brillouin optical fiber sensing device and method. The dynamic distributed Brillouin optical fiber sensing device comprises a narrow linewidth laser, a polarization-maintaining coupler, a coupler, a first electro-optic intensity modulator, a pulse signal generator, a frequency shifter, an optical amplifier, a polarization scrambler, an optical circulator, a polarization controller, a second electro-optic intensity modulator, a microwave signal source, a sensing optical fiber, a 3dB coupler, a balanced photoelectric detector and a data acquisition and processing module. Two technologies including a Brillouin gain spectrum dual-slope frequency point assisted method and a coherent detection technology are adopted at the same time. The coherent detection technology can increase the signal-noise ratio of a system, improve the measurement precision and increases the sensing distance; the Brillouin gain spectrum dual-slope frequency point assisted method solves a problem of influence of optical power fluctuation of a pumping pulse on the measurement precision in a conventional Brillouin gain spectrum slope frequency point assisted method. Therefore, the dynamic distributed Brillouin optical fiber sensing device and method can realize dynamic event measurement with relatively high measurement precision while guaranteeing that the Brillouin optical fiber sensing system has relatively long sensing distance.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a dynamic distributed Brillouin optical fiber sensing device and method. Background technique [0002] Optical fiber Brillouin optical time-domain analysis technology (BOTDA) is a distributed optical fiber sensing technology based on the stimulated Brillouin scattering effect. ) are respectively injected into both ends of the fiber, when the frequency difference of the two beams of light is within the range of Brillouin gain, energy transfer occurs between the two beams of light due to the stimulated Brillouin effect; the frequency sweep of the probe light point by point can be obtained The Brillouin Gain Spectrum (BGS) distribution along the sensing fiber, from which the distribution of the Brillouin Frequency Shift (BFS) along the sensing fiber can be obtained, using the proportional relationship between the frequency shift and temperature / strain and the optical t...

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Problems solved by technology

[0004] What the present invention aims to solve is the problem that the measurement accuracy is seriously affected by the fluctuation of the pump light power in the Brillouin gain slope method BOTDA dynamic sensing technology, and provides a dynamic distributed sensor based on coherent detection and BGS double slope frequency point auxiliary method. The Brillouin fiber optic sensing device and method can realize dynamic event measurement with high measurement accuracy while ensuring the Brillouin fiber optic sensing system has a long sensing distance

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