High sensitivity sensors based on open cavity in-fiber Fabry–Perot and Mach–Zehnder interferometers

Abstract

Two open cavity in-fiber Fabry–Perot and Mach–Zehnder interferometers are fabricated and their liquid refractive index and temperature sensing characteristics are comparatively studied, respectively. In our experiments, for the Fabry–Perot interferometric sensor, its dip wavelength versus refractive index and temperature sensitivity is 50.001 nm/RIU (refractive index unit) for a refractive index range from 1.3351 to 1.3737 and 0.016 nm/deg, respectively. For the Mach–Zehnder with Fabry–Perot cavity sensor, its dip wavelength versus refractive index and temperature sensitivity is 587.089 nm/RIU at a 1.3331–1.3415 refractive index range, −647.755 nm/RIU at a 1.3415–1.3737 refractive index range, and 0.032 nm/deg, respectively.