A Temperature Fiber Sensor Based on Tapered Fiber Bragg Grating Fabricated by Femtosecond Laser

A temperature fiber sensor based on tapered fiber Bragg grating (tapered FBG) fabricated by femtosecond laser has been proposed and realized with good reproducibility. Firstly, the fiber taper with 25 mu m diameter and 1000 mu m length is fabricated by arc-discharge elongation using two standard single-mode fibers. Secondly, two first-order FBGs are fabricated in tapered and non-tapered fiber regions for comparison. Both FBGs are point-by-point direct-written by femtosecond laser, and the grating lengths are 1000 mu m. Thirdly, a temperature experiment is performed using a heating chamber, and experimental results show that in the range of 30 similar to 350 degrees C, the temperature sensitivity of the tapered FBG has increased from 11.0 pm/degrees C to 12.3 pm/degrees C. The tapered FBG proposed here can be further configured for sensing other parameters in physical, chemical, and biomedical applications.