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
Affiliations
Qiu-Shun Li
Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China
Xu-Lin Zhang
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
Jian-Guo Shi
Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China
Dong Xiang
CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China
Lan Zheng
Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China
Yan Yang
Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China
Jun-Hui Yang
Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China
Dong Feng
Key Biosensor Laboratory of Shandong Province, Biology Institute of Shandong Academy of Sciences, Jinan 250014, China
Wen-Fei Dong
CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China
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.
