Rapid Brillouin optical-time domain analysis type strain measuring device and data processing method

Abstract

The invention relates to a stimulated Brillouin gain spectral linewidth narrowing processing, pulse coding and wavelet transform technology-based high-performance rapid Brillouin optical-time domain analysis type (BOTDA) strain measuring device and a data processing method and belongs to the distributed optical fiber sensing technical field. The measuring device is composed of a laser 1, a first optical coupler 2, a first modulator 3, a first microwave signal source 20, a first optical filter 4, a second modulator 5, a second microwave signal source 21, a direct-current power source 22, an optical amplifier 6, a second optical coupler 7, an optical isolator 8, a second modulator 9, a frequency synthesizer 14, a second optical filter 10, a fourth modulator 11, a pulse signal generator 15, a scrambler 12, an optical circulator 13, a sensing optical fiber 19, a photoelectric detector 16, a data acquisition card 17 and a computer 18. According to the measuring device and the data processing method of the invention, three pump signals are adopted to realize optical fiber stimulated Brillouin scattering gain spectral linewidth narrowing processing, and therefore, the precision of a BOTDA strain measurement system can be improved; pulse encoding and wavelet transform technology are combined to improve a signal-to-noise ratio, and therefore, measurement accuracy can be improved, and measurement time can be shortened.

Description

technical field [0001] The invention belongs to the technical field of distributed optical fiber sensing, and specifically relates to a high-performance fast BOTDA (Brillouin optical time-domain analysis type) based on the combination of stimulated Brillouin gain spectrum line width narrowing processing, pulse coding and wavelet transform technology ) Strain measuring device and data processing method. Background technique [0002] Optical fiber sensors have the advantages of small size, light weight, high sensitivity, high pressure resistance, corrosion resistance, good electrical insulation, anti-electromagnetic interference, etc., and are widely used in structural detection of communication optical cables, embankments, concrete, pipelines, tunnels, bridges, etc. . The distributed optical fiber sensor based on the stimulated Brillouin scattering effect uses the linear relationship between the stimulated Brillouin frequency shift and the strain, and obtains the correspondi...

AI Technical Summary

Problems solved by technology

Since the BOTDA system uses the stimulated Brillouin scattering effect of optical fiber to measure strain, the Brillouin gain linewidth directly affects the measurement accuracy of strain. The wider the Brillouin gain linewidth, the lower the strain measurement accuracy.

The measurement time of the BOTDA system is also a key factor. The current method to reduce the time is to use coding technology to improve the signal-to-noise ratio, thereby reducing the number of measurements and shortening the measurement time. However, when the order of coding is too high, the measurement time of the system will also decrease not conducive to reducing

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