High sensitivity optical fiber temperature sensor based on PDMS-filled with extended measuring range

In this paper, a novel high-sensitivity optical fiber temperature sensor with extended measurement range is proposed, and it is implemented experimentally by cascading FP interferometer and fiber Bragg grating (FBG). In this structure, the FBG is employed to determine the temperature range initially, and then the FP interferometer is used to obtain the precise temperature value. Experimental results indicate that the proposed scheme is fruitful and feasible, and the sensor has the temperature sensitivity of − 3.24 nm/°C with a high linear response (R2 = 0.9971) in the range of 30–50 °C. When the temperature rises from 50 °C to 70 °C, the sensitivity and linearity of the sensor are − 3.13 nm/°C and R2 = 0.9966, respectively. In addition, the stability of the proposed sensor has also been verified. Besides ultrahigh sensitivity and the approximate linear temperature sensing performance, this compact fiber optic sensor has advantages of miniature size, convenient fabrication, good reproducibility, making it promising in temperature fluctuations monitoring.