Wavelength-demodulation MEMS Fabry Perot temperature sensor based on bimetallic diaphragm

A novel wavelength-demodulation MEMS optical fiber temperature sensor based on a bimetallic diaphragm is presented. The sensor is designed by following the basic principle of optical Fabry – Perot interference and the bimetallic diaphragm effect. The mechanical model of the bimetallic diaphragm with the mesa structure is validated by simulation and the ANSYS software is used to optimize the sensor structure. By tracing a peak point in the interference spectrum, the gap length of the sensor can be demodulated. Experimental results demonstrate a temperature-induced cavity length change of 0.407 nm/°C with a good linearity and reasonable accuracy in the range of 20 – 70 °C. The proposed sensor could be fabricated as sensor arrays for micro level applications, thus reducing production costs considerably.