| Fiber grating sensor has the characteristic of anti-jamming capability, Fiber grating sensor has the advantages of anti-jamming capability, high security, more measurement characteristic quantities, large measurement dynamic range and so on. It can be widely applied in distributed sensing. The fiber grating Fabry-Perot cavity sensors, combining the characteristics of fiber gratings with Fabry-Perot cavity, have the advantages of high precision sensing, flexible demodulation method, easy to reuse. The application of Fourier transform demodulation,can bring about the frequency division multiplexing use fiber grating Fabry-Perot sesnors of different cavity length in different wavelength ranges, which can greatly increase the number of sensors multiplexed. Besides that, because this method completes the multiple signal demodulation by computer, we can simplify the structure and improve stability for demodulation system.In this dissertation, the mechanism of fiber grating F-P cavity on temperature and differential strain measurement has expounded and the transmission spectra of fiber grating F-P cavity in Fourier frequency domain is analyzed. The method to detect temperature and differential strain simultaneously by fiber Bragg grating Fabry-Perot cavity sensor and with Fourier transform demodulation is proposed., The fiber Bragg grating F-P cavity sensor is fabricated. The experiment on the measurement of absolute strain and differential strain is carried out.. Experimental results show that the sensor is able to measure the absolute change in temperature and the differential strain with the accuracy of0.24℃and±19με, respectively.In order to enlarge the measuring range, the method to detect dual parameter by chirped grating Fabry-Perot cavity.sensor is presented. Its feasibility is analyzed by numerical simulation. The results show that the method can achieve a wide range measurement of temperature and the differential strain. |
PDF Full Text Request