A Distributed Optical Fiber Sensing System for Simultaneous Measurement of Temperature, Strain and Vibration

Abstract

The invention discloses a distributed optical fiber sensing system for simultaneously measuring temperature, strain and vibration. The invention is based on time-division multi-OTDR multiplexing technology, and uses optical time-division multiplexed unequal-width double pulses as detection light. The coherent detection technology of Brillouin scattering signal and Rayleigh scattering signal is integrated to realize a distributed optical fiber sensing system capable of single-ended measurement of temperature, strain and vibration, and the measurement vibration frequency range can reach MHz level, which solves both The traditional OTDR system can only measure temperature or static strain, and cannot respond to dynamic changes in time, or it is difficult to simultaneously measure temperature and strain, and the measurable vibration frequency range is limited by the length of the sensing fiber. The system can perform single-ended measurement, has a simple structure, is easy to implement, and has broad application prospects.

Description

technical field [0001] The invention relates to a distributed optical fiber sensing system, in particular to a technique based on optical time-division multiplexing of unequal-width double pulses to obtain backward Brillouin scattered light signals and backward Rayleigh scattered light signals in optical fibers to realize Time-division multi-optical time domain reflectometry (OTDR) distributed optical fiber sensing system for simultaneous measurement of multiple parameters of temperature, strain and vibration. Background technique [0002] With the continuous construction and use of large-scale infrastructure, online safety and health monitoring, fault prevention and timely detection of large-scale bridge civil structures, oil pipelines, highways, railways and other facilities have also received more and more attention. However, due to the large span of such basic engineering facilities, the complex structure and environment, traditional monitoring methods (such as the use o...

AI Technical Summary

Problems solved by technology

Although this technology has been applied in distributed vibration sensors, the existing distributed optical fiber sensing systems used to measure vibration are mostly double-ended measurement or loop structures, and once there is a break in the optical fiber, the entire system will fail

At the same time, its detectable frequency range is limited by the length of the sensing fiber

[0006] At present, there are no relevant reports on the research of distributed optical fiber sensing systems that can simultaneously detect strain, temperature, and high-frequency vibrations, but the demand for distributed optical fiber sensing systems that can simultaneously detect strain, temperature, and high-frequency vibrations is increasing day by day

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