High-sensitivity strain sensor based on in-fiber rectangular air bubble

Shen Liu,Kaiming Yang,Changrui Liao,Junle Qu,Bing Sun,Yiping Wang,Guanjun Wang,Jing Zhao,Jiangtao Zhou,Jun He,Zhengyong Li,Guolu Yin,Jian Tang

doi:10.1038/srep07624

Abstract

We demonstrated a unique rectangular air bubble by means of splicing two sections of standard single mode fibers together and tapering the splicing joint. Such an air bubble can be used to develop a promising high-sensitivity strain sensor based on Fabry-Perot interference. The sensitivity of the strain sensor with a cavity length of about 61 μm and a wall thickness of about 1 μm was measured to be up to 43.0 pm/με and is the highest strain sensitivity among the in-fiber FPI-based strain sensors with air cavities reported so far. Moreover, our strain sensor has a very low temperature sensitivity of about 2.0 pm/°C. Thus, the temperature-induced strain measurement error is less than 0.046 με/°C.

Highlights

Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
We demonstrated a unique rectangular air bubble by means of splicing two sections of standard single mode fibers together and tapering the splicing joint
Sensitive strain measurements by use of optical fiber sensors are very attractive in many applications such as structure health monitoring, aerospace, and nanotechnology[1,2,3]

Summary

Introduction

Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China. We demonstrated a unique rectangular air bubble by means of splicing two sections of standard single mode fibers together and tapering the splicing joint Such an air bubble can be used to develop a promising high-sensitivity strain sensor based on Fabry-Perot interference. Fabry-Perot interferometers (FPIs) based on an in-fiber air cavity were proved to be outstanding in lots of sensing applications, such as strain measurements[12,13,14,15,16,17,18,19], refractive index (RI) measurements[20,21] and pressure measurements[22,23], due to the advantages of simple configuration, high sensitivity, compact size, and low temperature cross-sensitivity. The rectangular air-bubble-based FPI could be used to develop a promising high-sensitivity strain sensor with a low temperature sensitivity

Methods

Results

Conclusion