A simple method for demodulation of long-period fiber grating signals

In this paper, a comprehensive evaluation of a long period fiber grating sensor (LPFGs) based on the transmission intensity at a fixed wavelength is presented. Firstly, the application of spiral long-period fiber grating sensor (H-LPFGs)and tapered long-period fiber grating sensor (T-LPFGs) based on transmission intensity at fixed wavelength is studied, that is, the sensor of torsion, temperature, strain and liquid concentration. The transverse pressure and temperature are then evaluated using this method, and the optical signal is converted into an electrical signal using photoelectric conversion to prepare a complete LPFGs. The temperature sensor has a voltage-temperature sensitivity of -18.7mV/ ℃for a measuring range of 50-150℃ with an accuracy of 0.1℃, and the strain sensor has a voltage-strain sensitivity of 0.248 mV/με for a measuring range of 0-1800με with an accuracy of 1 με. Compared with other long - period fiber grating sensors, the accuracy is improved and the measurement range is wider. The demodulation system of the LPFG sensor based on the transmission intensity ratio measurement method has the advantages of simple operation, wide application range, and low price, so it has a very good application prospect in the LPFG sensor.