Citation: Mireles, J., Jr.; Sauceda, Á.; Jiménez, A.; Ramos, M.; Gonzalez-Landaeta, R. Design and Development of a MOEMS Accelerometer Using SOI Technology. Micromachines 2023, 14, 231. https://doi.org/10.3390/ mi14010231 Academic Editor: Ha Duong Ngo Received: 28 December 2022 Revised: 10 January 2023 Accepted: 12 January 2023 Published: 16 January 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). micromachines Article Design and Development of a MOEMS Accelerometer Using SOI Technology José Mireles, Jr. 1,2 , Ángel Sauceda 1,2 , Abimael Jiménez 1,2, *, Manuel Ramos 1,3 and Rafael Gonzalez-Landaeta 2 1 Applied Science and Technology Research Center, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, 450 Avenida del Charro, Ciudad Juárez 32310, Mexico 2 Electrical and Computer Engineering Department, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, 450 Avenida del Charro, Ciudad Juárez 32310, Mexico 3 Department of Physics and Mathematics, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, 450 Avenida del Charro, Ciudad Juárez 32310, Mexico * Correspondence: abimael.jimenez@uacj.mx Abstract: The micro-electromechanical system (MEMS) sensors are suitable devices for vibrational analysis in complex systems. The Fabry–Pérot interferometer (FPI) is used due to its high sensitivity and immunity to electromagnetic interference (EMI). Here, we present the design, fabrication, and characterization of a silicon-on-insulator (SOI) MEMS device, which is embedded in a metallic package and connected to an optical fiber. This integrated micro-opto-electro-mechanical system (MOEMS) sensor contains a mass structure and handle layers coupled with four designed springs built on the device layer. An optical reading system using an FPI is used for displacement interrogation with a demodulation technique implemented in LabVIEW ® . The results indicate that our designed MOEMS sensor exhibits a main resonant frequency of 1274 Hz with damping ratio of 0.0173 under running conditions up to 7 g, in agreement with the analytical model. Our experimental findings show that our designed and fabricated MOEMS sensor has the potential for engineering application to monitor vibrations under high-electromagnetic environmental conditions. Keywords: vibration measurement; micro-opto-electro-mechanical system (MOEMS); silicon-on- insulator (SOI); Fabry–Pérot interferometry; demodulation 1. Introduction The development of monitoring technology for high-power machinery, including the conditions of harsh electromagnetic environments and machining operation applications, requires vibratory analysis as an essential tool that can be used to reduce costs and su- pervisory times [1–7]. However, most of the recent investigations on vibration analysis for applications where strong electromagnetic forces are present faced problems such as strong interface noise ratios in the sensing structures and signal-conditioning electronic interfaces [8–10]. Dedicated micro-electro-mechanical system (MEMS) displacement sensors are micro- electronic devices that are suitable for vibrational analysis. These sensors are designed to monitor mobile MEMS components using sensing principles such as capacitance [11,12], electromagnetics [13,14], photodiode-based principles [15,16], and lasers or optics [17,18]. Each sensing principle has its own advantages and disadvantages depending on the sensing mechanism used on the micro-scale. For instance, capacitive sensors convert capacitance changes into displacement information by measuring the physical gap between the two plates. However, their performance is proportional to the plate area [11]. Electromagnetic sensors detect the intensity change of an electric current induced by a magnetic field [13]; however, a good electric shield around the engaged current-sensing element is necessary to avoid any interference in the measurement. Micromachines 2023, 14, 231. https://doi.org/10.3390/mi14010231 https://www.mdpi.com/journal/micromachines