Measurement of Structural Loads Using a Novel MEMS Extrinsic Fabry–Perot Strain Sensor

Yufang Bai,Dakai Liang,Zhuming Cheng,Jiwei Huang,Jie Zeng,Shaolong Zhong

doi:10.3390/app10010018

Abstract

In this paper, microelectromechanical systems (MEMS) technology was used to fabricate a novel extrinsic fiber Fabry–Perot (EFFP) strain sensor; this fiber sensor is applied to measure load with higher precision for a small structure. The sensor cavity consists of two Fabry–Perot (FP) cavity mirrors that are processed by surface micromachining and then fused and spliced together by the silicon–glass anode bonding process. The initial cavity length can be strictly controlled, and the excellent parallelism of the two faces of the cavity results in a high interference fineness. Then, the anti-reflection coating process is applied to the sensor to improve the clarity of the interference signal with the cavity, with its wavelength working within the range of the C + L band. Next, the sensor placement is determined by the finite element software Nastran. Experimental results indicate that the sensor exhibits a good linear response (99.77%) to load changes and a high repeatability. Considering the strain transfer coefficient, the sensitivity for the tested structure load is as high as 35.6 pm/N. Due to the miniaturization, repeatability, and easy-to-batch production, the proposed sensor can be used as a reliable and practical force sensor.

Highlights

Fiber optic sensors are desirable in engineering measurement due to their advantages such as small size, anti-electromagnetic interference, high resolution, and reusability [1,2]
As a basic physical parameter, the strain can be successfully measured by sensors including the fiber Bragg grating [3,4], interferometric fiber-optic sensor [5,6,7] and distributed fiber sensor [8,9]
FP force sensors; the theory of the axial contact force sensor reported by [13] corroborated that the wavelength of interference dip will have a shift as the applied axial force increases

Summary

Introduction

Fiber optic sensors are desirable in engineering measurement due to their advantages such as small size, anti-electromagnetic interference, high resolution, and reusability [1,2]. As a basic physical parameter, the strain can be successfully measured by sensors including the fiber Bragg grating [3,4], interferometric fiber-optic sensor [5,6,7] and distributed fiber sensor [8,9]. The Fabry–Perot (FP) sensors are an attractive choice, owing to their compact structure, and especially their advantages in terms of sensitivity and high-temperature resistance [10,11,12]. Implemented a new fiber-optical force sensor as a modular sensor used in surgery. Domingues et al proposed an intrinsic cost-effective FP sensor by splicing two optical fibers previously destroyed by the catastrophic fuse effect [18]. The sensor was embedded into a polymer casing with a maximum sensitivity of

Results

Discussion

Conclusion