High Speed Demodulation System of FBG-EFPI Hybrid Sensor Based on Fourier Domain Mode-Locked Laser

The complicated sensor FBG-EFPI with high speed demodulation has become one of the central issues of optical fiber sensing field in the engineering application. Currently, the existing FBG-FP composite sensor has problems such as complicated fabrication and slow demodulation. Aiming at these problems, this paper proposes a new high-speed demodulation method based on Fourier domain mode-locked(FDML) laser. Different from the pulsed light reflected in the optical time domain, this paper uses continuous light scanning, the scanning frequency can reach 40khz, and the scanning range is about 20nm. Experiment result shows the temperature sensitivity of FBG and EFPI are 10.9pm/°C and 0.42pm/°C respectively with the temperature change from 20 °C, and at room temperature, with the strain change from 0~500ue, the strain sensitivity of FBG and EFPI are 1.17pm/µe and 1.24pm/µe respectively.