Ultra-long distance distributed optical fiber vibration sensing detection method and device

Abstract

The invention relates to the technical field of optical fiber communication, and provides an ultra-long distance distributed optical fiber vibration sensing detection method and device, and the method comprises the following steps: arranging N optical repeaters in a sensing optical fiber link at a certain interval, the distance between the adjacent optical repeaters is determined by the attenuation coefficient of the sensing optical fiber link section between the two optical repeaters and the amplification gain coefficient of the next optical repeater; inputting detection light into the sensing optical fiber, wherein the detection light is transmitted in the downlink optical transmission link; when the sensing optical fiber is influenced by vibration, back Rayleigh scattering light generated by vibration is transmitted back to back in the uplink direction, and the back Rayleigh scattering light enters an uplink optical transmission link through a loopback link in the nearest optical repeater; the backward Rayleigh scattering light is subjected to optical power amplification through an amplifier of the optical repeater in the uplink optical transmission link and then returns to the optical fiber vibration sensing detection system, and the optical fiber vibration sensing detection system analyzes the backward Rayleigh scattering light to obtain a vibration position.

Description

technical field [0001] The present invention relates to the technical field of optical fiber communication, and more particularly, to an ultra-long-distance distributed optical fiber vibration sensing detection method and device. Background technique [0002] Distributed fiber optic vibration sensors include interferometric sensors and backscatter sensors. The formation of Rayleigh scattering in optical fibers mainly originates from the non-uniformity of material density and refractive index due to various reasons during the optical fiber fabrication process. The optical fiber distributed sensor based on interference technology is mainly based on the phase modulation characteristics of the external disturbance signal to the light wave transmission in the optical fiber, and realizes the sensing and detection of the external disturbance signal by demodulating the phase information change of the returned light wave signal. The traditional Optical Time-Domain Reflectometry (OTD...

AI Technical Summary

Problems solved by technology

However, in long-distance optical communication, the back Rayleigh scattering signal intensity generated when light is transmitted in the optical fiber is weak, so the detection distance is generally less than 40km

Even if the external disturbance to the optical fiber is very strong, when the distance between the disturbance source and the distributed sensing system exceeds 40km, the back Rayleigh scattering signal will be attenuated when transmitted in the optical fiber, which will cause the signal to be greatly weakened, or even unable to be transmitted. Therefore, the detection distance of the current distributed sensing system has certain limitations.

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