Analysis of a fiber-optic deep-etched silicon Fabry–Perot temperature sensor and modeling its fabrication imperfections

Design and fabrication of an in-plane silicon Fabry–Perot temperature sensor for fiber-optic temperature sensing was reported in our previous work. To fabricate this sensor, deep reactive ion etching process was utilized which is challenging due to the large depth of etching needed for the device. Required optically smooth surfaces and highly vertical sidewalls as well as minimum amount of under-etch are difficult to be achieved in deep-etched structures. Here, the fabrication errors are briefly introduced and thereafter a numerical analysis based on the transfer-matrix formulation for propagation of Gaussian beams across the proposed silicon Fabry–Perot resonator is developed. Finally, the fabricated sensor is modeled and the device performance degradation due to fabrication imperfections is estimated.