Intrinsic fiber Fabry-Perot temperature sensor fabricated by a femtosecond laser

A Fabry-Perot (F-P) interferometer was inscribed in a standard single mode fiber by inducing refractive index changes in the core. It was written directly by using a femtosecond laser. The reflection spectrum of the F-P interferometer was measured, and was investigated as a temperature sensor. The sensitivity is 9.2pm/°C in the range of -20~80°C.