High-precision fiber grating sensor array demodulating system based on holographic diffraction space imaging

Abstract

The invention discloses a high-resolution high-precision fiber grating sensing demodulating system based on holographic diffraction space imaging. The system is used for monitoring the changes of the wave lengths of multiple fiber grating sensors with high precision. The system comprises a broadband light source, a coupler, a photoswitch, a fiber grating array, a holographic diffraction space imaging unit, a CCD photoelectric detection unit, a data collecting unit, a self-adaption digital-analog hybrid smoothing unit for imaging optoelectronic signals, a digital-analog hybrid noise cancellation and processing unit, a data iteration fitting and correlation analyzing and processing unit and a computer display and data processing and storing unit, and the fiber grating array is formed by connecting more than two fiber gratings in series. The holographic diffraction space imaging unit is formed by connecting a beam shaping unit, a holographic diffraction crystal unit and a space imaging objective lens unit in sequence. According to the system, the high-precision and high-resolution detection of the wave lengths of the fiber grating sensors can be achieved, stability and repeatability are good, and the system is simple in structure, low in cost and high in cost performance.

Description

technical field [0001] The invention relates to a high-resolution and high-precision distributed optical fiber grating sensor array demodulation technology based on holographic diffraction space imaging, which is used to realize high-precision monitoring of wavelength changes of multiple optical fiber grating sensors. Background technique [0002] With the application of fiber grating sensing technology in structural health monitoring (SHM) and other projects, due to the small structural strain, there is an increasing need for fiber grating sensing and demodulation systems with high resolution, high precision and high sensitivity. The technologies currently used for FBG demodulation mainly include scanning filter method, interferometer method and so on. However, research and engineering practice show that the resolution and accuracy of sensing systems of these technical methods are limited at present, and actual engineering sometimes requires higher measurement resolution an...

AI Technical Summary

Problems solved by technology

However, research and engineering practice show that the resolution and accuracy of sensing systems of these technical methods are limited at present, and actual engineering sometimes requires higher measurement resolution and accuracy, such as long-term health monitoring of some large-scale engineering structures such as long-span bridges and tunnels. Monitoring, due to the small change in strain, often requires higher resolution and accuracy of the sensing demodulation system to accurately measure the degree of structural damage, which is of great significance to the long-term health monitoring of the structure

Images