Fiber grating Fabry-Perot cavity vibration sensor and vibration measurement system thereof

Abstract

The invention relates to a fiber grating Fabry-Perot (F-P) cavity vibration sensor and a vibration measurement system thereof. The invention is technically characterized in that a fiber grating F-P cavity is stuck to the middle position of a cantilever beam; and one end of the cantilever beam is fixed on a support, and the other end thereof is connected with a mass block. The measurement system using the vibration sensor is characterized in that one side of the intensity-demodulation type fiber grating F-P cavity vibration sensor is extended into a fiber index-matching liquid, and the other side thereof is connected with the port of a terminal B of a fiber circulator via single-mode fiber; a terminal A of the fiber circulator is connected with a narrow-band light source; and a terminal C of the fiber circulator is connected with a photoelectric detector. By adopting the fiber grating F-P cavity, optical signals can resonate in the F-P cavity to form interference peaks, so that the accuracy of the detection can be greatly increased; meanwhile, by adopting the intensity-demodulation manner of narrow-band light source irradiation, the detection frequency of the vibration sensor can be increased from a few hertz to hundreds of hertz; and the invention can measure the frequency and amplitude of weak vibration signals at the same time, and improve the measurement accuracy.

Description

technical field [0001] The invention relates to a fiber grating Fabry-Perot cavity vibration sensor and a vibration measurement system thereof, which are used for measuring the frequency and amplitude of weak vibration of objects, and belong to the technical field of optical fiber sensing. Background technique [0002] The measurement of weak vibration is widely used in micro-electromechanical systems, civil engineering, highway bridges, electrical equipment, pacemaker control, seismic waves, precision vibration isolation platform detection and other fields. For example, through the real-time monitoring of the weak vibration generated when the equipment is working, it can be judged whether its working state is abnormal, and the fault can be eliminated in time to avoid accidents. [0003] Traditional vibration sensors generally use electrical quantities for sensing. This type of sensor has poor reliability in outdoor environments, is susceptible to electromagnetic interferenc...

AI Technical Summary

Problems solved by technology

However, the biggest disadvantage of the single FBG vibration sensor is that the measurement accuracy is limited, and the detection ability for weak vibration signals is insufficient.

At the same time, most FBG vibration sensors demodulate the wavelength, and for most wavelength demodulators, the highest response frequency is only a few Hz, which cannot measure vibration information at higher frequencies, and the wavelength demodulation equipment The price is generally more expensive, thus limiting its development

Images