Abstract
In this paper, an underwater fiber-optic sensor based on surface plasmon resonance (SPR) and multimode interference (MMI) is presented for simultaneous measurement of salinity and pressure. This sensor is based on a single-mode-multimode-single-mode-multimode-single-mode structure with a gold film deposited on the middle single-mode fiber and the fiber structure is wrapped around an elastic cylinder to constitute a sensing head. In the fiber structure, the SPR region produces a resonance dip to measure salinity, and the independent MMI region achieves narrow and salinity-insensitive interference dips to measure pressure. Performance of the sensor is predicted by calculation, and the MMI spectrum is simulated by using the finite-difference beam propagation method. By experimental tests for salinity and pressure, the sensitivities of 0.36 nm/‰ and $-{1.42}\;{\rm nm}/{\rm MPa}$ are achieved, respectively, and the cross talk is also proved to be insignificant. This study provides an important application direction for SPR-MMI sensors and a prospective method for ocean detection.
© 2021 Optical Society of America
Full Article | PDF ArticleMore Like This
Yu Zhang, Meijiang Liu, Yaxun Zhang, Zhihai Liu, Xinghua Yang, Jianzhong Zhang, Jun Yang, and Libo Yuan
Appl. Opt. 59(4) 1225-1229 (2020)
Yadira-Aracely Fuentes-rubio, René-Fernando Domínguez-Cruz, and José-Rafael Guzmán-Sepúlveda
Appl. Opt. 60(31) 9691-9695 (2021)
Ding Xue, Hongxia Zhang, Shuang Wang, Hongzhi Li, Junfeng Jiang, Dagong Jia, and Tiegen Liu
Opt. Express 31(20) 33241-33252 (2023)