Applications Of Double Fiber Bragg Gratings In FBG Sensors

The principle of temperature and strain measurements using fiber Bragg gratings is described. The response characteristic of fiber Bragg grating with temperature and strain is measured.A new scheme of wavelength detection and demodulation technique of fiber Bragg grating sensors with double fiber Bragg gratings is presented. The experiments of possible schemes of this technique are made and the experiment results are compared.The principle of cross-sensitivity of strain and temperature of fiber Bragg grating sensors is described. The temperature compensation techniques in common use of fiber Bragg grating apparatus using in optical fiber communication are presented. The simultaneous measurement of strain and temperature and the temperature compensation of fiber Bragg grating sensors for strain measurement are realized using double fiber Bragg gratings. The influence on measurement precision of fiber Bragg grating sensors caused by cross-sensitivity is eliminated.A new fiber Bragg grating sensors multiplexing system is developed using the novel wavelength detection and demodulation technique and spatial division multiplex technique. The multiplexing numbers are not confined by bandwidth of light source and tunable scope of single fiber Bragg grating.