High-consistency fiber-optic Fabry-Perot sensor based on MEMS for simultaneous temperature and liquid refractive...

We proposed a hybrid Fabry-Perot fiber-optic sensor based on the microelectromechanical system (MEMS) technique for measuring temperature and liquid refractive index simultaneously, and we verify the consistency of four sensors in the same batch. The sensor consists of a groove-array structured glass wafer and two silicon wafers, which are connected by double-sided anodic bonding. The three parts form two independent Fabry-Perot cavities for temperature and liquid refractive index sensing, respectively. We randomly selected three sensors in the same batch and conducted temperature and refractive index experiments to establish the sensing equation. The experimental results demonstrate their high consistency with temperature sensitivities of 81.6, 81.8, and 81.4 pm/°C in the range of 10°C to 80°C, and refractive index sensitivities of 1040.11, 1044.24, 1042.91 nm/RIU in the range of 1.333-1.374. The sensors have low cross-sensitivities that are less than 5.86×10^-6 RIU/°C and high precisions of 0.047°C, 2.14×10^-6RIU, respectively. To verify the validity of the sensing equation, we made another sensor in the same batch and got maximum errors of 0.36°C and 7.7×10^-5RIU, respectively.