An Ultrasensitive Long-Period Fiber Grating-Based Refractive Index Sensor with Long Wavelengths

Qiu-Shun Li; Xu-Lin Zhang; Jian-Guo Shi; Dong Xiang; Lan Zheng; Yan Yang; Jun-Hui Yang; Dong Feng; Wen-Fei Dong

doi:10.3390/s16122205

An Ultrasensitive Long-Period Fiber Grating-Based Refractive Index Sensor with Long Wavelengths

Sensors (Basel). 2016 Dec 21;16(12):2205. doi: 10.3390/s16122205.

Authors

Qiu-Shun Li¹, Xu-Lin Zhang², Jian-Guo Shi³, Dong Xiang⁴, Lan Zheng⁵, Yan Yang⁶, Jun-Hui Yang⁷, Dong Feng⁸, Wen-Fei Dong⁹

Affiliations

¹ Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China. liqs06@mails.jlu.edu.cn.
² State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China. xulin_zhang@jlu.edu.cn.
³ Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China. shijg@sdas.org.
⁴ CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China. xd789@mail.ustc.edu.cn.
⁵ Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China. zhengl@sdas.org.
⁶ Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China. swdz2@sdas.org.
⁷ Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China. swdz@sdas.org.
⁸ Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China. shenghua@sdas.org.
⁹ CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China. wenfeidong@sibet.ac.cn.

Abstract

The response of a novel long-period fiber grating (LPFG) with a period of 180 µm to a surrounding refractive index (RI) was investigated. The results displayed that, with the increase in RI of the surrounding media of cladding glass in the grating region, the resonant peak located at 1336.4 nm in the transmission spectrum gradually shifts towards a shorter wavelength, while the resonant peak located at 1618 nm gradually shifted towards a longer wavelength. Moreover, the resonant peak at 1618 nm is much more sensitive to the surrounding RI than that of the one at 1336.4 nm. Compared with the conventional LPFG and other types of wavelength-interrogated RI sensors, such as ring resonators, surface plasmon resonance sensors, and Fabry-Perot interferometric sensors, this novel LPFG possesses a higher sensitivity, which achieved 10,792.45 nm/RIU (RI unit) over a RI range of 1.4436-1.4489.

Keywords: long wavelength; long-period fiber grating; refractive index; sensor; transmission spectrum.