This study proposes a novel interferometric fiber optic SPR sensor which is able to realize both the temperature and the strain sensing with high sensitivity. Firstly, it is fabricated by splicing a no core fiber between two single-mode fibers to form the multimode interference structure. Then, half-length of the no core fiber is deposited by the gold film layer to form the classic three-layer SPR sensor. Finally, PDMS is covered onto the whole surface of the no core fiber, which performs as a medium to convert the external temperature changes into its refractive index variations. When compared with the other fiber optic sensors, the proposed sensor realizes the temperature and strain measurements based on two independent sensing mechanisms, particularly speaking, the temperature sensing is realized based on the SPR mechanism, and the strain sensing is realized based on the multimode interference. Hence, its inherent cross-sensitivity can be largely suppressed since the two sensing mechanisms are independent of each other. Besides, the proposed sensor shows both high-temperature sensitivity (1.13 nm/℃) and strain sensitivity (54.1 pm/με), which is suitable for the dual-parameter measurements.

Date Published: 12 March 2020
PDF: 6 pages
Proc. SPIE 11436, 2019 International Conference on Optical Instruments and Technology: Optical Sensors and Applications, 114360B (12 March 2020); doi: 10.1117/12.2543444

Published in SPIE Proceedings Vol. 11436:
2019 International Conference on Optical Instruments and Technology: Optical Sensors and Applications
Xuping Zhang; Hai Xiao, Editor(s)