System and method for measuring disturbance based on POTDR

Abstract

The invention discloses a system for measuring the disturbance based on the POTDR, and the system employs a method which comprises the following steps: dividing a detection pulse into two cross-polarization components with the same energy through introducing a polarization beam splitter and a polarization beam combiner, combining the cross-polarization components together through small time delay, and enabling the combined detection pulse light to be transmitted to a polarization analyzer through a circulator and a connection optical fiber, wherein the polarization analyzer is disposed at the front end of a sensing optical fiber, the detection pulse passes through the polarization analyzer to enter the optical fiber, the backward rayleigh scattered light of the optical fiber enters an avalanche detector through the circulator, and the polarization signal along the optical fiber is sensed through signal analysis. The system achieves the simultaneous measurement of the disturbance in multiple optical fibers through the introduction of a coupler and connection optical fibers with different lengths. The invention also discloses a disturbance measurement method based on the POTDR, and the system and method eliminate the impact on the sensing and detection from the unrelated disturbance on the connection optical fibers between a POTDR system and sensing optical fibers, and are strong in anti-interference capability. The system can achieve the simultaneous detection of the disturbance of a plurality of independent regions through multiplexing.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a POTDR-based disturbance measurement system and method. Background technique [0002] Optical fiber sensing technology is a brand-new technology developed from the 1970s. With the practical application of optical fibers and the development of optical communication technology, optical fiber sensing technology has developed rapidly in a diversified manner. When light is transmitted in the optical fiber, due to the influence of external disturbance, temperature, strain, displacement and other environmental factors on the optical fiber, the polarization state, power, wavelength, phase and other parameters of the optical signal will change. By detecting these parameters of the light in the optical fiber, the change information of the environment around the optical fiber can be obtained, thereby realizing sensing. [0003] When a beam of short-pulse light is incident on...

AI Technical Summary

Problems solved by technology

[0005] Because the polarization state of the light in the fiber will change with the external disturbance to the fiber connected to the POTDR, the stability of the POTDR system is poor, and when the light is transmitted in the fiber, the change of the polarization state is continuous. If there is disturbance, the Rayleigh scattering signal transmitted back from the fiber under test will be covered up, and the accuracy of sensing will be affected

Traditional POTDR sensing technology has the defect of poor anti-interference ability

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