Sensitivity Enhancement of Strain Sensing Utilizing a Differential Pair of Fiber Bragg Gratings

Sensors

Zhiyong Zhang¹  Lianshan Yan¹  Wei Pan¹  Bin Luo¹  Ping Wang²  Likang Guo² 

[1] Center for Information Photonics & Communication, School of Information Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 614202, China; E-Mails:;Lab of Railway Engineering, School of Civil Engineering, Southwest Jiaotong University, Chengdu, Sichuan 614202, China; E-Mails:

关键词: fiber Bragg grating;    strain measurement;    differential pair of FBG;    sensitivity;    railway safety monitoring;   

DOI  :  10.3390/s120403891

来源: mdpi

【 摘 要 】

In strain measurement applications, the matched fiber Bragg gratings (FBG) method is generally used to reduce temperature dependence effects. The FBG parameters have to be designed to meet the requirements by the particular application. The bandwidth and slope of the FBG has to be balanced well, according to the measurement range, accuracy and sensitivity. A sensitivity enhanced strain demodulation method without sacrificing the measurement range for FBG sensing systems is proposed and demonstrated utilizing a pair of reference FBGs. One of the reference FBGs and the sensing FBG have almost the same Bragg wavelength, while the other reference FBGs has a Bragg wavelength offset relative to the sensing FBG. Reflected optical signals from the sensing FBG pass through two reference FBGs, and subtract from each other after the detection. Doubled strain measurement sensitivity is obtained by static rail load experiments compared to the general matched grating approach, and further verified in dynamic load experiments. Experimental results indicate that such a method could be used for real-time rail strain monitoring applications.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.