A long-distance high-resolution Brillouin optical time-domain analysis method

Abstract

The invention discloses a long-distance high-resolution Brillouin optical time-domain analysis method, comprising the following steps: generating pulsed light 1, pulsed light 2, frequency-sweeping continuous light 1 and frequency-sweeping continuous light 2; The pulsed light 2 is injected from the end of the optical fiber 2 to be tested; the continuous light 1 is injected from the head end of the transmission fiber 1 and emitted from the end of the transmission fiber 1, and then injected into the end of the optical fiber 1 to be tested, and the continuous light 2 is injected from the transmission fiber 1 The end of the second is injected into and emitted from the first end of the transmission fiber two and then injected into the first end of the second optical fiber to be tested; the first probe light is formed in the first optical fiber to be tested, and the second probe light is formed in the second optical fiber to be tested; the light of the first probe light is collected strong and converted into digital signal 1, the light intensity of detection light 2 is collected and converted into digital signal 2; measurement data 1 and measurement data 2 are obtained by calculation; measurement data 1 and measurement data 2 are spliced ​​to obtain final measurement data; the invention measures Long distance, good precision and high spatial resolution.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to a long-distance high-resolution Brillouin optical time-domain analyzer. Background technique [0002] Compared with Brillouin Optical Time Domain Reflectometer (BOTDR) and other distributed optical fiber sensing systems, Brillouin Optical Time Domain Analyzer (BOTDA) has fast measurement speed, long measurement distance, high spatial resolution, and measurement The advantages of high precision; such as figure 1 As shown, in the existing BOTDA, the optical fiber adopts a U-shaped back-and-forth configuration loop structure; pulsed pump light and continuous probe light are injected from both ends of the fiber, the frequency of the pulse pump light is fixed, and the frequency of the continuous probe light Scan back and forth to realize the scanning of the optical fiber Brillouin spectrum, thereby realizing the temperature and strain sensing of the optical fiber. [000...

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Problems solved by technology

[0006] According to the existing technology described in the background technology of this patent, the current solutions for improving the long-distance measurement accuracy of BOTDA include heterodyne detection, near-end pumping amplification of the host, and remote pumping amplification at the far end. The former solution is complicated and difficult to implement, while the latter However, the long-distance high-resolution Brillouin optical time-domain analysis method disclosed in the present invention, from the head end of the photoelectric composite cable to the photoelectric composite cable A pulsed light is injected into the optical fiber to be tested, and a continuous light is emitted. The continuous light is amplified near the end of the photoelectric composite cable, and then goes from the end of the photoelectric composite cable to the test fiber in the photoelectric composite cable. Optical fiber 1 is injected, thereby measuring the measurement data from the first end of the optical fiber composite cable to the end of the optical fiber 1 to be tested as measurement data 1; at the same time, injecting 1 optical fiber 2 from the end of the optical composite cable to the optical fiber 2 to be tested in the optical composite cable. A beam of pulsed light is emitted, and a beam of continuous light is emitted. The continuous light is amplified at a position close to the head end of the photoelectric composite cable, and then enters from the head end of the photoelectric composite cable to the second optical fiber to be tested in the photoelectric composite cable, thereby measuring Obtain the measurement data of the optical fiber 2 to be tested from the end of the photoelectric composite cable to the head end as the measurement data 2; the measurement accuracy of the measurement data 1 is higher near the head end of the photoelectric composite cable, and the measurement accuracy of the measurement data 2 is higher near the end of the photoelectric composite cable. And the first optical fiber to be tested and the second optical fiber to be tested are any two single-mode optical fibers in the same photoelectric composite cable. The measurement system 1 and the measurement system 2 have the same long measurement time and measure at the same time. The final measurement data with high precision is obtained by splicing the first and the second measurement data, thus realizing long-distance measurement, the measurable distance is at least 100km, and the spatial resolution is high and the measurement accuracy is good

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