Research On Strain Sensing Technology Based On Opto-electronic Oscillator

As a new interdisciplinary subject,microwave photonics(MWP)has been developed continuously,breaking through more and more fields.Among them,photoelectric oscillator(OEO)has attracted a lot of attention because of its high quality microwave signal,wide frequency range,relatively low phase noise and tunable signal.In the field of sensing,an attempt is made to combine the photoelectric oscillator with the optical fiber sensor to form a microwave photon sensor.This kind of sensor can not only have the above advantages of the photoelectric oscillator,but also have the advantages of low loss,large bandwidth,anti-electromagnetic interference and multiplexing.These advantages actively promote the further development of optical fiber sensor.In this paper,the optical fiber sensing technology based on photoelectric oscillation system is studied.Based on the(OEO)loop of the photoelectric oscillator,the phase modulator,which used to replace the intensity modulator,and the phase-shifted fiber(PSFBG)is used to construct the microwave photonic filter.The sensing of corresponding variables is realized based on the sensitivity of corresponding variables in the grating region of phase-shifted fiber Bragg grating.In this paper,the background development and parameter characteristics of photoelectric oscillator and fiber sensing technology are introduced in detail,and the spectral characteristics and sensing mechanism of phase shift optical fiber grating(PSFBG)are introduced.The main work is as follows: the performance of single-loop photoelectric oscillator in laboratory environment is studied,and the methods to improve the frequency stability of the output signal under the existing conditions are analyzed;the strain system based on phase-shifted fiber grating is constructed;Fiber optic sensors with different lengths are introduced into the loop of the sensing system to study the strain sensing experiments,and the performance of these fiber grating sensors based on photoelectric oscillator is studied one by one.At the end of the paper,the dynamic vibration sensing is designed on the basis of static strain sensing.