Method for detecting fiber distributive pipeline vibration signal based on multi-core fiber cable

Abstract

The invention relates to the technical field of optical engineering, fiber optics and signal processing, and in particular to a method for detecting fiber distributive pipeline vibration signal based on a multi-core fiber cable. The method comprises the following steps: a) a narrow line width laser transmitting a pulse optical signal through an electro-optical modulator having high extinction ratio, the optical signal entering a fiber cable of a sensor apparatus which is constituted by multi-core fiber cables; b) receiving the optical signal which is reflected from the sensor apparatus, a microwave signal source synchronously triggering a data acquisition card for data acquisition, the acquired data entering a signal processing apparatus for conducting further signal processing; c) in the signal processing apparatus which processes the acquired signals, processing the signals so as to acquire time-domain information contained in the vibration and acoustic signals at different positions of the fiber imposed by the pipeline. The method has high signal-to-noise ratio, high sensitivity and simple structure, and has wide applications in the field of fiber distributive vibration sensing.

Description

【Technical field】 [0001] The invention relates to the technical fields of optical engineering, optical fiber optics and signal processing, in particular to a method for detecting vibration signals of optical fiber distributed pipelines based on multi-core optical cables. 【Background technique】 [0002] At present, in the detection of vibration signals received by long-distance pipelines, the traditional distributed sensing system has the following problems: [0003] 1) Due to the limited signal-to-noise ratio and sensitivity of the traditional distributed sensing system, and the effective vibration signal on the pipeline is transmitted through the air and absorbed by the medium, the signal obtained by single-core optical fiber detection is very weak, making it very difficult to detect effective signals. [0004] 2) Due to the traditional interferometric distributed sensing technology based on the principle of phase sensing, this type of technology generally has problems such...

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Problems solved by technology

[0003] 1) Due to the limited signal-to-noise ratio and sensitivity of the traditional distributed sensing system, and the effective vibration signal on the pipeline is transmitted through the air and absorbed by the medium, the signal obtained by single-core optical fiber detection is very weak, making it very difficult to detect effective signals

[0004] 2) Due to the traditional interferometric distributed sensing technology based on the principle of phase sensing, this type of technology generally has problems such as limited system signal-to-noise ratio and sensitivity, short positioning distance, shielded optical fiber, complex data processing, and polarization state fading, which are serious. Affect the sensing performance of the system, making the positioning accuracy of the sensing system lower

[0005] 3) The traditional distributed sensing system can only realize the measurement and positioning of a single position and cannot achieve multi-point positioning

[0006] 4) The detection signal of the traditional distributed sensing system is affected by many noise sources, and it is random noise or statistical noise

In some application scenarios that require high precision and high sensitivity, the low signal-to-noise ratio of traditional distributed sensing systems will greatly reduce the value of the sensing system

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