Vibration broadband measurement system and method based on multi-wavelength weak reflection structure sensing optical fiber

Abstract

The invention discloses a vibration broadband measurement system and method based on a multi-wavelength weak reflection structure sensing optical fiber. A first measurement system comprises the multi-wavelength weak reflection structure sensing optical fiber and a multi-wavelength light source. The multi-wavelength light source is sequentially connected with a first wavelength division multiplexer, an acoustic / optical modulator, an optical amplifier and a first port of a circulator, wherein a second port and a third port of the circulator are connected with the multi-wavelength weak reflectionstructure sensing optical fiber and a second wavelength division multiplexer respectively; and the output of the second wavelength division multiplexer is connected with a phase demodulation module.A second measurement system comprises the multi-wavelength weak reflection structure sensing optical fiber and a pulse light source; the pulse light source is connected with the first ports of the plurality of circulators; the second port of each circulator is connected with the multi-wavelength weak reflection structure sensing optical fiber; and the third ports of all the circulators are connected with the phase demodulation module. The two forms of measurement systems both improve the pulse repetition frequency, the frequency response range of vibration measurement is effectively improved when the length of the optical fiber is fixed, and the system performance is improved.

Description

technical field [0001] The invention relates to the technical field of distributed optical fiber sensing, in particular to a vibration broadband measurement system and method based on multi-wavelength weak reflection structure sensing optical fibers. Background technique [0002] In recent years, with the rapid development of oil and gas pipelines, oil wells, large-scale industries and buildings, their safety has attracted more and more attention from all walks of life, especially the monitoring of the health of long-distance infrastructure. Due to the many advantages of distributed optical fiber sensing technology, it can realize the ability to obtain the measured distribution information on the optical fiber with time and space in a large range. Distributed optical fiber sensing vibration measurement currently has Mach-Zehnder interferometer technology, phase-sensitive optical time-domain reflectometry (OTDR) technology, frequency division multiplexing technology and white...

AI Technical Summary

Problems solved by technology

Distributed optical fiber sensing vibration measurement currently has Mach-Zehnder interferometer technology, phase-sensitive optical time-domain reflectometry (OTDR) technology, frequency division multiplexing technology and white light interference technology, and after research, the phase-sensitive OTDR technology is the most important in vibration measurement In order to avoid crosstalk between Rayleigh scattering signals, this technology requires only one light pulse to occur in each measurement cycle. When the sensing fiber is very long, the light pulse reflection time increases, making The lower the repetition rate of the light pulses, the narrower the range of vibrational frequencies that can be measured

Images