Abstract:A dual parameter fiber sensor based on Long Period Fiber Grating (LPFG) cascaded with Fiber Bragg Grating (FBG) structure for temperature and strain is presented. The proposed fiber sensor is cascaded with LPFG micromachined by the femtosecond laser and FBG, and there are two dips for the transmission spectrum, namely FBG transmission dip at 1 551.9 nm and LPFG transmission dip at 1 559.1 nm with the fringe contrast -12.7 dB. The temperature and strain characteristics of the proposed sensor were measured at 30~70℃ and 0~500 με, respectively. Experimental results show that during the warming process, the FBG shows red shift with increasing wavelength, the sensitivity is 15.00 pm/℃, and the linearity is 0.981 3; The LPFG shows blue shift with decreasing wavelength, the sensitivity is -11.75 pm/℃, and the linearity is 0.945 3. During the cooling process, the FBG shows blue shift with decreasing wavelength, the sensitivity is 18.25 pm/℃, and the linearity is 0.953 8; The LPFG shows red shift with decreasing wavelength, the sensitivity is -15.42 pm/℃, and the linearity is 0.980 2. During the loading process, the FBG shows red shift with increasing wavelength, the sensitivity is 0.93 pm/με, and the linearity is 0.991 5; The LPFG shows blue shift with decreasing wavelength, the sensitivity is -1.51 pm/με, and the linearity is 0.986 3. During the unloading process, the FBG shows blue shift with decreasing wavelength, the sensitivity is 0.92 pm/με, and the linearity is 0.990 9; The LPFG shows red shift with decreasing wavelength, the sensitivity is -1.51 pm/με, and the linearity is 0.972 8. The proposed sensor exhibits high sensitivity and good linearity for dualparameter measurements.