High-sensitivity MOEMS gyroscope utilizing the sub-wavelength grating–waveguide mode coupling effect

Micro-electro-mechanical system (MEMS) gyroscopes based on the Coriolis principle have numerous potential applications, including industrial automation, motion control, inertial navigation, and automotive systems. In this paper, we present a novel (to our knowledge) micro-opto-electro-mechanical system (MOEMS) gyroscope design based on the grating–waveguide mode coupling effect. This diffraction phenomenon enables highly sensitive displacement detection, even nanoscale shifts in the grating elements induce a dramatic change in optical diffraction efficiency, exhibiting anomalous diffraction behavior. Using RSoft software, we systematically simulate and investigate the influence of sub-wavelength grating parameters on diffraction efficiency and determine the optimal geometric configuration. Furthermore, we conduct a comprehensive tolerance analysis to evaluate the impact of fabrication accuracy on diffraction intensity. Finally, we develop a Simulink-based system model for the gyroscope. The designed system achieves a structural sensitivity of 0.09 nm/°/s, an optical diffraction sensitivity of 0.679 mW/nm, and a photoelectric conversion sensitivity of 44.5 mV/mW, yielding a total sensitivity of 2.72 mV/°/s. The proposed sub-wavelength grating MOEMS gyroscope not only addresses critical limitations of conventional MEMS gyroscopes but also demonstrates strong potential for inertial-grade MEMS gyroscopes with unprecedented precision.