Multi-parameter distributed measurement system and measuring method of dual-core weak grating array based on dark pulse light source

Abstract

The invention relates to a multi-parameter distributed measurement system and measuring method of a dual-core weak grating array based on a dark pulsed light source. The system includes a broadband dark pulse light source, a weak grating array, a dual-core fiber, a photoelectric conversion unit, a fiber delay line, a notch filter, an information collection unit, a computer, a dual-core fiber coupler. The system utilizes high-intensity Rayleigh scattered light excited by high-power stable background light of a pulse width tunable dark pulse light source for distributed measurement; meantime, the system uses the dark pulse and weak grating array of the light source to carry out spatial segmented positioning of the Rayleigh scattering in the whole fiber range in order to improve the spatial resolution and measurement precision of a sensing system, and realizes simultaneous precise measurement of temperature and strain and precise positioning in an interval. The system has the advantages of simple structure, fast response speed and high spatial resolution, and can realize the distributed optical fiber sensing measurement of temperature and strain parameters at the same time with high precision.

Description

technical field [0001] The invention relates to a multi-parameter distributed measurement system, more specifically, relates to a multi-parameter distributed measurement system based on a double-core weak grating array of a dark pulse light source. Background technique [0002] With the development of science and technology and the improvement of the application requirements of the Internet of Things, the optical fiber sensing network is developing in the direction of large capacity and multi-parameter measurement. The distributed optical fiber sensing network based on Rayleigh scattering, Brillouin scattering and Raman scattering is The measurement of physical parameters such as temperature and strain at various points continuously distributed in space in high voltage, strong magnetic field interference, high current, complex geometric space, flammable, explosive and other harsh environments provides a feasible new method. Distributed optical fiber sensing technology is dev...

AI Technical Summary

Problems solved by technology

However, the distributed optical fiber sensing system based on single-mode optical fiber Rayleigh scattering uses the weak back Rayleigh scattering signal as the information carrier, the signal-to-noise ratio of the system is low, the measurement accuracy and spatial resolution are low, and the sensing function is relatively simple. , it is difficult to realize quantitative detection of temperature and strain, etc., which restricts the development of distributed optical fiber sensing technology based on Rayleigh scattering

Especially because the optical fiber is sensitive to temperature and strain, it is difficult to ensure that the optical fiber is not disturbed by stress by adding an additional temperature-sensitive optical fiber, and the position deviation between the temperature compensation grating and the measurement grating will make the measurement accuracy difficult. Guaranteed, there are difficulties in engineering applications

At present, there is no report on the continuous distributed optical fiber sensing of strain and temperature at all positions along the optical fiber using a weak fiber grating array.

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