Multi-parameter large-capacity sensing system

Abstract

The invention relates to the technical field of fiber grating sensing, in particular to a multi-parameter large-capacity sensing system comprising a narrow-line-width pulse laser, an erbium-doped optical amplifier, a circulator, a matching interferometer, a reflected light detecting unit, and a computer that are connected successively by a fiber. The circulator is connected with an eccentric fiber; and an ultra-low reflectance grating array is engraved on the eccentric fiber. According to the system based on the reasonable structure, the ultra-low reflectance grating array of the eccentric fiber is used as a sensing unit to obtain a strong evanescent field, so that the system detection sensitivity and the signal-to-noise ratio are greatly improved; with the phi-OTDR technology, the Rayleigh scattering light is amplified effectively and the location of the signal point is determined by the delay between the detection input light and the received light, thereby realizing multi-point measurement; and on the basis of the coherent detection technique, the phase change of the interference signal between the adjacent eccentric ultra-low reflectivity gratings is detected under the effect of the external signal to demodulate the external signal, thereby realizing multi-parameter large-capacity detection on the temperature, vibration and strain.

Description

technical field [0001] The invention relates to the technical field of fiber grating sensing, in particular to a multi-parameter and large-capacity sensing system. Background technique [0002] With the development of optical fiber sensing technology and the rapid improvement of its sensing ability, the optical fiber sensing network is developing towards the direction of large capacity and multi-parameter measurement. In fiber optic sensing technology, fiber grating sensing technology is a very important sensing technology. In addition to all the advantages of optical fiber sensing technology, it also has some unique advantages: many gratings can be written in a single optical fiber to form a sensing array and realize distributed sensing. Traditional fiber grating sensing adopts wavelength division multiplexing, limited by the bandwidth of the light source, the number of sensors that can be multiplexed on a single fiber is only dozens. [0003] Weak fiber gratings are wide...

AI Technical Summary

Problems solved by technology

However, for physical quantities such as temperature and strain, only positioning detection is possible, and dynamic quantitative real-time monitoring cannot be realized.

[0005] Existing sensing systems that use weak gratings as sensing units to measure multiple parameters have problems such as low sensitivity of the detection system, insufficient measurement accuracy, and low signal-to-noise ratio of the system.

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