Optical fiber delay line-based distributed optical fiber vibration sensing system

Abstract

The invention discloses an optical fiber delay line-based distributed optical fiber vibration sensing system, which comprises a light emitting unit, an optical fiber ring element which is connected with the light emitting unit and a sensing optical fiber, a beam splitter which is connected with the optical fiber ring element and used for splitting a backscattering light beam into a first backscattering light beam and a second backscattering light beam and outputting the backscattering light beams respectively, an optical fiber delay line which is connected with one output end of the beam splitter and used for delaying the second backscattering light beam, a light combiner which is connected with the optical fiber delay line and the other output end of the beam splitter and used for combining the first backscattering light beam and the delayed second backscattering light beam, an APD light receiving module which is connected with the light combiner, an AD collector connected with the light receiving module, and a light analysis and display system which is used for analyzing the electrical signal collected by the AD collector to obtain the vibration position of the sensing optical fiber. The system has the advantages of high positioning precision and high interference measurement technique sensitivity.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a distributed optical fiber vibration sensing system based on optical fiber delay lines. Background technique [0002] The concept of fiber optic sensors is not new, as early as the mid-1960s, the first patents appeared, which include Fotonic mechanical displacement sensors using beam transmission and ultrasonic sensors using phase modulation. However, in a broader field, that is, optical fiber sensing technology, it was only 10 years later that a series of research was achieved. Since then, optical fiber technology has broken through the stagnant state and entered an era of rapid progress. [0003] The basic principle of the optical fiber sensor is: the light emitted by the light source enters the modulation area through the optical fiber. Under the action of the measured object, the optical properties such as the intensity, wavelength, frequency, phase, and polari...

AI Technical Summary

Problems solved by technology

However, the detection area of ​​the distributed optical fiber vibration sensor with optical fiber delay line is very large, the longer the measuring optical cable, the better, generally greater than 50Km, and the spatial resolution of the defense zone is 10m, so the dynamic range of light receiving of the system is very wide (greater than 50dB), real-time The processing data is very large, and the requirements for the photoelectric signal processing system are extremely high, so there are very few domestic manufacturers that can produce distributed optical fiber vibration sensors with stable performance.

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