Rahimi Mojtaba, Taghavi Majid, Malekmohammad Mohammad
Appl Opt. 2022 Jan 10;61(2):629-637. doi: 10.1364/AO.439762.
A coarse-to-fine optical microelectromechanical systems (MEMS) accelerometer based on the Fabry-Pérot (FP) interferometer is proposed. The mechanical structure consists of a proof mass that is suspended by four L-shaped springs. The deflection of the proof mass due to the applied acceleration is detected using two FP cavities that comprise the system's optical system. Using coarse-to-fine measurement and the dual wavelength method simultaneously increases the sensitivity of the accelerometer as well as the linear measurement range. The optical simulation shows that the sensitivity of the proposed device is 10 times as high as that of a similar optical MEMS accelerometer with one FP cavity. In addition, the proposed optical system is insensitive to the displacements of the proof mass in the orthogonal directions, which considerably reduced the cross-axis sensitivity. The minimum feature size of the structure is 15 µm and the optical signal is conducted completely through the optical fibers, facilitating the device fabrication. Here are the results of the simulation: mechanical sensitivity of 190 nm/g, optical sensitivity of 8 nm/g, linear measurement of ±5, and first resonance frequency of 1141 Hz.
提出了一种基于法布里-珀罗（FP）干涉仪的粗-精光学微机电系统（MEMS）加速度计。其机械结构由一个通过四个L形弹簧悬挂的质量块组成。利用构成系统光学系统的两个FP腔来检测由于施加加速度而导致的质量块的偏转。同时采用粗-精测量和双波长方法，既提高了加速度计的灵敏度，又扩大了线性测量范围。光学仿真表明，所提出器件的灵敏度是具有一个FP腔的类似光学MEMS加速度计的10倍。此外，所提出的光学系统对质量块在正交方向上的位移不敏感，这大大降低了交叉轴灵敏度。该结构的最小特征尺寸为15μm，光信号完全通过光纤传导，便于器件制造。以下是仿真结果：机械灵敏度为190nm/g，光学灵敏度为8nm/g，线性测量范围为±5，第一共振频率为1141Hz。
