High-Sensitivity MOEMS Gyroscope Based on Photonic Crystal Wavelength Modulation

In this article, a two-dimensional (2-D) tunable photonic crystal wavelength-modulated micro-opto-electro-mechanical system (MOEMS) gyroscope is reported. The device consists of a mechanical structure and an optical structure. The vibrating mass block of the mechanical structure is driven by an electrostatic force that generates a Coriolis force under the action of the applied angular velocity to displace the sensitive unit. The sensitive unit movement changes the photonic crystal cavity of the optical structure, resulting in a change in the resonant wavelength in the transmission spectrum. The external applied angular velocity is obtained by detecting the shift of the resonance wavelength. We have analyzed the dynamic characteristics of the mechanical structure by numerical simulation and obtained a mechanical sensitivity with 0.335648 nm/(
$^{\circ }/\text {s}$
). Notably, we analyzed the optical signal response characteristics of the optical structure using the finite-difference time-domain (FDTD) method and the rigorous coupled-wave analysis (RCWA) method. The simulation results show that the sensitivity of the optical system is 1.11142 nm/(nm) in the near-infrared region. Strikingly, the proposed sensor has an optomechanical sensitivity of 0.373 nm/(
$^{\circ }/\text {s}$
) and a resolution of
$1.34^{\circ }/\text {s}$
in the range of
$\pm 1040^{\circ }/\text {s}$
. By introducing 2-D tunable photonic crystals, the performance of MOEMS gyroscopes is largely improved, making them potentially attractive for applications in automotive autonavigation and agricultural aircraft attitude control.