Closed-Loop MOEMS Accelerometer

TL;DR

This paper introduces a silicon-based closed-loop MOEMS accelerometer utilizing a Fabry-Pérot interferometer and electrostatic feedback to enhance measurement range and resolution.

Contribution

It presents a novel closed-loop MOEMS accelerometer design with integrated optical and electrostatic components for improved performance.

Findings

Linear response in 5 g range

Sensitivity of 1.16 V/g

Bias instability of 40 g

Abstract

In this paper, a closed-loop micro-opto-electro-mechanical system (MOEMS) accelerometer based on the Fabry-P\'erot (FP) interferometer is presented. The FP cavity is formed between the end of a cleaved single-mode optical fiber and the cross-section of a proof mass (PM) which is suspended by four U-shaped springs. The applied acceleration tends to move the PM in the opposite direction. The arrays of fixed and movable comb fingers produce an electrostatic force which keeps the PM in its resting position. The voltage that can provide this electrostatic force is considered as the output of the sensor. Using a closed-loop detection method it is possible to increase the measurement range without losing the resolution. The proposed sensor is fabricated on a silicon-on-insulator wafer using the bulk micromachining method. The results of the sensor characterization show that the accelerometer has a linear response in the range of 5 g. In the closed-loop mode, the sensitivity and bias instability of the sensor are 1.16 V/g and 40 g, respectively.