Design and Fabrication of a Differential MOEMS Accelerometer Based on Fabry Perot micro-cavities

TL;DR

This paper presents a novel differential MOEMS accelerometer utilizing Fabry-Perot micro-cavities, fabricated on SOI wafers, demonstrating enhanced sensitivity and linear response in static acceleration measurements.

Contribution

The paper introduces a differential Fabry-Perot MOEMS accelerometer with improved sensitivity, fabricated via bulk micromachining on SOI wafers, and demonstrates its superior performance over single-cavity designs.

Findings

Linear response in 1g range

Optical sensitivity of 6.52 nm/g

Sensor sensitivity doubled compared to single-cavity design

Abstract

In this paper, a differential MOEMS accelerometer based on the Fabry-Perot (FP) micro-cavities is presented. The optical system of the device consists of two FP cavities and the mechanical system is composed of a proof mass that is suspended by four springs. The applied acceleration tends to move the PM from its resting position. This mechanical displacement can be measured by the FP interferometer formed between the proof mass cross-section and the optical fiber end face. The proposed sensor is fabricated on a silicon on insulator (SOI) wafer using the bulk micromachining method. The results of the sensor characterization show that the accelerometer has a linear response in the range of 1g. Also, the optical sensitivity and resolution of the sensor in the static characterization are 6.52 nm/g and 153ug. The sensor sensitivity in the power measurement is 49.6 mV/g and its resonant is at 1372 Hz. Using the differential measurement method increases the sensitivity of the accelerometer. Based on experimental data, the sensor sensitivity is two times as high as that of a similar MOEMS accelerometer with one FP cavity.