Optical fiber pipeline detection device based on 2*2 coupler and double Faraday rotator mirrors

Abstract

The invention discloses an optical fiber pipeline detection device based on a 2*2 coupler and double Faraday rotator mirrors. The optical fiber pipeline detection device comprises a sensing optical fiber detection system, a signal demodulation system, a signal communication and processing system and a signal analysis and human-computer interaction system, wherein the sensing optical fiber detection system comprises an ASE high-power light source, a first single-mode optical fiber, an optical isolator, a second single-mode optical fiber, a first coupler, a delay optical fiber, a phase modulator, a polarization controller, a second coupler, a first sensing optical fiber and a second sensing optical fiber; a light signal is emitted from the light source to detect a pipeline through the sensing optical fiber detection system, and then is converted into an electric signal through a photoelectric converter; the signal is demodulated, is processed by a DSP and then is transmitted to a computer through a communication system for signal analysis and human-computer interaction. The optical fiber pipeline detection device provided by the invention is more suitable for detecting underwater long-distance pipeline transportation, has better detection sensitivity and a more stationary sensing light path, and reduces the demodulation difficulty.

Description

technical field [0001] The invention belongs to the field of pipeline leakage detection, in particular to an optical fiber pipeline detection device based on 2×2 couplers and double Faraday rotating mirrors. Background technique [0002] With the improvement of people's lives, pipeline transportation is becoming more and more necessary, from natural gas pipeline transportation to underwater oil and gas pipeline transportation, and even pipeline transportation for the West-East Gas Pipeline Project, etc. However, we also have higher requirements for the safety of pipeline transportation, so it is particularly important to detect whether the pipeline is leaking. [0003] Chinese invention patent application 201110302312.4 is based on hybrid interference type distributed optical fiber underwater long-distance pipeline leak detection device, in which the entire sensing core part is laid by a sensing optical fiber in the interlayer on one side of the pipeline, and a sensing optic...

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Problems solved by technology

[0003] Chinese invention patent application 201110302312.4 is based on hybrid interference type distributed optical fiber underwater long-distance pipeline leak detection device, in which the entire sensing core part is laid by a sensing optical fiber in the interlayer on one side of the pipeline, and a sensing optical fiber senses The disadvantage of measuring the entire pipeline is that if the long-distance pipeline is detected, the farther the leak point is from the Faraday rotating mirror, the lower the sensitivity of the entire detection system will be.

Because the Faraday rotating mirror is at one end of the pipeline, the detection sensitivity of the leak point will be greatly reduced when the leak point is close to the Faraday rotating mirror and far away from the Faraday rotating mirror when performing long-distance pipeline leak detection, which will cause pipeline leakage. of false positives or hard-to-detect defects

[0004] Chinese invention patent application 200610113044.0 is based on Sagnac optical fiber interferometer for pipeline leakage detection. Although two independent sensing optical fibers are used to form the sensing part of the system, the system is complicated and consists of multiple couplers, which is costly and complicated in structure. At the same time, it has high requirements on the use environment, which is not conducive to quick use

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