A microfiber Fabry-Perot interferometer (FPI) which employs two fiber Bragg Gratings (FBGs) as reflection mirrors and
a short length microfiber as its cavity is proposed and fabricated. Theoretic study shows that the reflection spectrum of
such microfiber FPI is consisted of two parts - interference fringes induced by FPI and reflection band induced by FBGs.
Temperature affects both parts while ambient refractive index only influences the first part, i.e. microfiber FPI has
different response to temperature and RI. Therefore, Dual-parameter measurement is experimentally demonstrated by
tracking the FSR variation and the central wavelength shift of the reflection spectrum of microfiber FPI.
A high sensitive temperature sensor based on Mach-Zehnder interferometer (MZI) is proposed and experimentally
demonstrated. Temperature measurement is achieved by immerging a section of microfiber into the refractive index (RI)
liquid with a high thermo-optic coefficient. A slight change of ambient temperature will lead to the enhanced variation
of the liquid index. Due to the evanescent field of microfiber, microfiber effective refractive index will be changed, and
subsequently the optical length. Thus, by measuring the free spectral range (FSR) of the MZI, the temperature sensor can
achieve a high sensitivity of 6.44nm/°C at the temperature of 20.6°C.