Distributed optical frequency domain reflection magnetic field sensing device based on magnetostriction and demodulation method

Abstract

The invention discloses a distributed optical frequency domain reflection magnetic field sensing device based on magnetostriction and a demodulation method, relating to the technical field of distributed optical fiber sensing instruments. The device comprises a main interferometer which obtains a sensing signal and an auxiliary interferometer which provides a clock trigger signal for a collection device, and a detected sensing fiber is packaged on a magnetostriction material. The method comprises the steps of obtaining different beat frequency signals at main interference through a light source of linear tuning, and converting wavelength domain information to distance domain information of each position in a corresponding sensing fiber by using rapid Fourier transform. The signal on the sensing fiber is selected through a mobile window, and then the conversion to a wavelength domain is carried out through plural rapid Fourier inverse transform, namely the Rayleigh scattering spectra. According to the distributed optical frequency domain reflection magnetic field sensing device and the demodulation method, the testing distance is raised, the spatial resolution and high, the accurate positioning of a multiple-point magnetic field can be carried out at the same time, the magnetic field strength can be measured at 5.3mT to the minimum, the testing distance can reach more than 300meters, and the magnetic field positioning accuracy can reach 14centimeters.

Description

technical field [0001] The invention relates to the technical field of distributed optical fiber sensing instruments, in particular to a magnetostrictive distributed optical frequency domain reflection magnetic field sensing device and a demodulation method. Background technique [0002] With the continuous development of society, the magnetic field in important areas such as medical treatment, electric power, and nuclear industry has a particularly important impact on their safety. The distributed optical fiber magnetic field sensing system can realize magnetic field detection and positioning, and has the characteristics of long-distance monitoring, high-precision positioning, low energy dependence, high environmental tolerance, and corrosion resistance. [0003] At present, there are mainly two types of distributed optical fiber magnetic field sensing. The first method is based on the polarization effect to measure the magnetic field. This method has the advantages of high...

AI Technical Summary

Problems solved by technology

[0003] At present, there are mainly two types of distributed optical fiber magnetic field sensing. The first method is based on the polarization effect to measure the magnetic field. This method has the advantages of high sensitivity and fast response, but the disadvantages of this method are: low magnetic field intensity resolution, It can only distinguish the magnetic field above 100mT. In addition, this method is seriously affected by the Faraday effect, and the test distance is relatively short, only about 15m

This method is characterized by high sensitivity to magnetic fields, but the disadvantage of this method is that the spatial resolution is low, probably above 1m

Images