Brillouin optical fiber sensing system and sensing method with adjustable frequency shifting structure

Abstract

The invention discloses a Brillouin optical fiber sensing system and sensing method with an adjustable frequency shifting structure. The Brillouin optical fiber sensing system is composed of a narrow-linewidth laser device, a first optical coupler, an optical amplifier, a scrambler, a second optical circulator, an erbium-doped fiber amplifier, a signal processing unit, a signal modulating unit, and an adjustable frequency shifting unit. In addition, the method includes: step one, generating continuous light; second two, generating pump light; step three, carrying out a stimulated Brillouin effect; step four, generating backscattered signal light; and step five, carrying out data collection and processing. The system having advantages of low cost and high system stability is capable of realizing distributed measurement of the temperature and strain. The sensing method is operated conveniently; the frequency shift adjustment is carried out conveniently; and the frequency shift is controlled easily. Meanwhile, the frequency modulation module employs the polarization maintaining device, so that the influence on light by the light polarization state is reduced and the obtained optical signal becomes stable.

Description

technical field [0001] The invention relates to the field of optical fiber sensing, in particular to a Brillouin optical fiber sensing system and sensing method with an adjustable frequency shift structure. technical background [0002] Optical fiber sensing technology has risen rapidly since the invention of optical fiber in the 1970s. After decades of research and development, it has been widely used in many fields such as optical fiber communication and optical fiber sensing. Due to the advantages of corrosion resistance and anti-electromagnetic interference of the optical fiber sensing system, compared with the traditional electromechanical sensing system, it is more suitable for detecting information in harsh environments, and has the ability of distributed sensing and long-distance sensing, so it has been distributed in recent years. Optical fiber sensing technology has become a research hotspot. [0003] Optical fiber Brillouin optical time-domain analysis technology...

AI Technical Summary

Problems solved by technology

In traditional BOTDA systems, electro-optic modulators with high extinction ratios and high-frequency microwave signal sources are often used as frequency shifting modules. The system cost is high, and electro-optic modulators with high extinction ratios have temperature drift and instability. Feedback control, resulting in complex system structure

Traditional BOTDA systems often use phase-locked loop technology (PLL) or optical sideband generation technology (OSB), which also brings about problems such as cost increase, long-term system stability, and system complexity.

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