A novel FPI sensor for high temperature sensing by Femtosecond Laser

We proposed and fabricated a V-shaped micro-cavity on single-mode fiber (SMF) by utilizing the Gaussian effect of femtosecond laser (fs-laser), which has been demonstrated for high temperature sensing. The processed compact probe sensor has an interference visibility about 5dB. As a novel high-temperature sensor, such a Fabry-Perot interferometer (FPI) has been tested in high temperature furnace of 800℃ for four times. The sensitivity is 13.72pm/℃ and has a good repeatability and stability. The fabrication process of this sensor head was quite easy, convenient, with potential of batch fabrication and easy calibration.