Multiparameter measurement depending on the cavity-length differentiation characteristics of a microfiber Fabry–Perot interferometer

Abstract

To solve the cross-sensitivity problem affecting optical fiber sensors and realize multiparameter measurement, a microfiber Fabry–Perot interferometer (MFPI) is proposed and experimentally demonstrated. Simultaneous measurement of two distinct physical parameter (temperature and strain) is realized by monitoring wavelength and reflectivity of MFPI. In the temperature field range of 22-36 ℃, the maximum temperature sensitivity can reach 12 pm/℃. The maximum strain sensitivity is up to 0.8 pm/με in the strain range of 0-800 με. In the simultaneous measurement experiments, the relative errors of temperature and strain were 4.0 % and 0.8%, respectively. Furthermore, the sensing element used in this method was just a single fiber grating sensor without any coating layer, which demonstrated the significant advantage of the proposed method in reducing the complexity and cost of multiparameter measurement.