A Brillouin Optical Time Domain Analysis System Based on Quasi-Distributed Passive Remote Pump Amplification

Abstract

The invention discloses a Brillouin optical time-domain analysis system based on quasi-distributed passive remote pump amplification. It is a quasi-distributed passive remote pump amplification structure, and multiple pump gain units are used to control the Brillouin optical time domain at different distances. The detection light and the pump pulse are amplified, which improves the sensing signal strength and measurement accuracy. At the same time, it can flexibly expand multiple sensing optical fibers to increase the sensing distance. And through the signal processing and management system, the strength and signal-to-noise ratio of the sensing signal in each section of the sensing fiber are analyzed, and then the front and rear pump power of the pump source and the Brillouin detection light emitted by the BOTDA front-end module are optimized in real time. The pump pulse power is used to make the intensity of the sensing signal injected into each section of the sensing fiber as similar as possible.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing and relates to a Brillouin optical time domain analysis system based on quasi-distributed passive remote pump amplification. Background technique [0002] Distributed optical fiber sensing uses ordinary single-mode optical fiber as the sensing medium and signal transmission medium at the same time, which can realize real-time measurement of physical quantities along the optical fiber. It has the advantages of long distance, distributed, and strong anti-electromagnetic interference. It has been used in large structures such as It has a wide range of applications in many fields such as stress, strain and temperature monitoring of bridges, liquid or natural gas pipeline leakage detection, and power grid system detection. [0003] At present, there are mainly optical fiber distributed sensing systems based on Rayleigh scattering, Raman scattering and Brillouin scattering, among which the...

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Problems solved by technology

However, distributed Raman amplification will introduce Raman spontaneous emission noise, pump-signal crosstalk, polarization-dependent gain, etc., which will reduce the signal-to-noise ratio of the signal and affect the measurement accuracy.

In addition, even with high-order Raman amplification with high pump power, the effective amplification distance is limited

Some researchers also use one or more online erbium-doped fiber amplifiers (EDFA) in the middle of the sensing line to effectively increase the sensing distance, but the remote EDFA needs an external power supply to work, which is difficult to achieve in the actual sensing system

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