COTDR measurement method and system based on sub-chirped pulse extraction

A chirped pulse and measurement method technology, applied in measurement devices, conversion sensor outputs, instruments, etc., can solve the problems of small measurement range and slow measurement speed of reflectometers, improve measurement efficiency, avoid time-consuming frequency sweeping process, The effect of widening the sweep range

Active Publication Date: 2019-08-16
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0005] The purpose of the present invention is to provide a COTDR measurement method based on sub-chirped pulse extraction and its system in o...

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  • COTDR measurement method and system based on sub-chirped pulse extraction

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Embodiment 1

[0067] see figure 1 As shown, the embodiment of the present invention provides a COTDR measurement method based on sub-chirped pulse extraction. The method steps include:

[0068] S101. Inject the chirped pulse signal into the optical fiber to be detected, and obtain the coherent Rayleigh scattering signal of the chirped pulse signal;

[0069] S102. Based on the coherent Rayleigh scattering signal, a sub-chirped pulse extraction algorithm is used to obtain the coherent Rayleigh scattering response of a series of sub-chirped pulse signals;

[0070] S103, based on the coherent Rayleigh scattering response of the chirped pulse signal, obtain the coherent Rayleigh scattering response pattern when the fiber is not disturbed and the coherent Rayleigh scattering response pattern when the fiber is disturbed; based on the coherence when the fiber is not disturbed and disturbed The Rayleigh scattering response pattern captures fiber perturbation information.

[0071] It can be unders...

Embodiment 2

[0100] It can be understood that the spectral range of the coherent Rayleigh scattering of the chirped pulse is consistent with the frequency range of the chirped pulse, and since the coherent Rayleigh scattering signal needs to be converted into the digital domain, the detection in the coherent detection module in the measurement system The bandwidth of the device needs to be greater than or equal to the bandwidth of the chirped pulse, and its sampling rate often needs to be more than twice the bandwidth of the chirped pulse. Due to the limitations of electrical detection and sampling equipment, the frequency sweep range of chirped pulses will also be limited to a certain extent. In order to solve this problem, further expand the frequency domain interval of the chirped pulse, refer to Figure 4 As shown, it shows another COTDR measurement system based on sub-chirped pulse extraction provided by Embodiment 2 of the present invention. The difference between its scheme and the ...

Embodiment 3

[0111] refer to Figure 6 As shown, the specific hardware structure of a COTDR measurement system based on sub-chirped pulse extraction provided by Embodiment 3 of the present invention, the measurement system 3 may include: a memory 32 and a processor 33; each component is coupled together through a communication bus 31 . It can be understood that the communication bus 31 is used to realize connection and communication between these components. In addition to the data bus, the communication bus 31 also includes a power bus, a control bus and a status signal bus. But for clarity, in Figure 6 The various buses are denoted as communication bus 31 in FIG.

[0112] Memory 32, used for storing the measurement method program that can run on the processor 33;

[0113] The processor 33 is configured to perform the following steps when running the measurement method program:

[0114] Step 1. Inject the chirped pulse signal p(t) into the optical fiber to be detected, and obtain th...

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Abstract

The invention discloses a COTDR measurement method based on sub-chirped pulse extraction and relates to the technical field of optical fiber sensing measurement. The method comprises the steps of injecting a chirped pulse signal into a to-be-measured optical fiber and obtaining a coherent Rayleigh scattering signal of the chirped pulse signal; on the basis of the coherent Rayleigh scattering signal, obtaining coherent Rayleigh scattering responses of sub-chirped pulse signals through adoption of a sub-chirped pulse extraction algorithm; on the basis of the coherent Rayleigh scattering responses of the sub-chirped pulse signals, obtaining coherent Rayleigh scattering response patterns when the optical fiber is disturbed and when the optical fiber is not disturbed; and on the basis of the coherent Rayleigh scattering response patterns when the optical fiber is disturbed and when the optical fiber is not disturbed, obtaining optical fiber disturbance information through utilization of a suitable delay estimation algorithm. The invention also discloses a COTDR measurement system based on the sub-chirped pulse extraction. According to the method, a frequency sweeping process is replacedby a sub-chirped pulse extraction process and the Rayleigh scattering signal is obtained, so measurement speed and a measurement dynamic range of an optical fiber sensing system can be improved.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing and measurement, in particular to a COTDR measurement method based on sub-chirped pulse extraction and a system thereof. Background technique [0002] Optical time domain reflectometer based on Rayleigh scattering is a very important branch in the field of distributed sensing, which has the advantages of high measurement accuracy, large number of measurement points, and long measurement distance. [0003] According to the sensing signal demodulation method, Rayleigh scattering-based optical time domain reflectometry can be divided into two categories: phase demodulation type and frequency demodulation type. The main application of phase demodulation type is phase sensitive optical time domain reflectometer (Φ-OTDR); the main application of frequency demodulation type is coherent optical time domain reflectometer (COTDR). Among them, for the existing coherent optical time domain refl...

Claims

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Application Information

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IPC IPC(8): G01D5/353
CPCG01D5/35361
Inventor 王子南熊吉吴悦饶云江
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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