Distributed optical fiber sensing device based on chaotic laser coherence method, and measurement method of distributed optical fiber sensing device

Abstract

The invention discloses a distributed optical fiber sensing device based on a chaotic laser coherence method, and a measurement method of the distributed optical fiber sensing device. Chaotic laser light which is emitted from a chaotic laser is divided into detection light and reference light; the detection light is amplified by a light amplifier and then emitted into a sending optical fiber through an optical circulator, and a backward Brillouin scattering light signal is generated in the optical fiber; the Brillouin scattering light signal is amplified by the light amplifier, de-noised by a tunable light filter and then emitted into an optical fiber coupler; the optical length of the reference light is regulated by a variable light delay line, and interferes with the backward Brillouin scattering light signal which is generated by the detection light at different positions in the sensing optical fiber in the optical fiber coupler; an interference beat frequency signal is detected by a photoelectrical detector; and Brillouin gain spectra at different lengths are obtained through a data acquisition device and a signal processing device and then output to a display device, so strain or temperature sensing detection is realized.

Description

technical field [0001] The invention relates to the technical field of distributed optical fiber sensors, in particular to a distributed optical fiber sensing device based on a chaotic laser coherence method and a measurement method thereof. Background technique [0002] Compared with traditional sensors, fiber optic sensors themselves are not charged, and have the advantages of anti-electromagnetic interference, electrical insulation, corrosion resistance, multi-parameter measurement, high sensitivity, lightweight, and can be embedded (objects), etc., and have been used in aviation, aerospace, and navigation. , petrochemical industry, electric power industry, nuclear industry, medical equipment, scientific research, construction, transportation and military and other fields have obtained important applications. [0003] Optical fiber sensors can be divided into three types: point type, quasi-distributed, and distributed according to their working methods. Among them, the p...

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Problems solved by technology

[0010] Among the above four distributed optical fiber sensing technologies, the advantages of BOTDA and BOTDR systems lie in the long measurement distance, which can reach more than 50 km. The disadvantage is that the spatial resolution is low. The best resolution can only reach about 1 m

The BOCDA and BOCDR systems have the advantage of high spatial resolution, which can reach the centimeter level. However, due to the influence of their frequency modulation correlation peak period characteristics, the measurement distance of the system is limited, and the current measurement distance cannot exceed 500 m.

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