Abstract

A temperature-compensated refractive index (RI) sensor based on thinned strongly-coupled seven-core fiber (SC-SCF) supermode Bragg grating and interferometer is demonstrated. The SC-SCF spliced between two standard single mode fibers was first tapered to 55.0 μm and then chemically etched to a waist diameter of 15.6 μm, forming a supermode interferometer. Bragg grating was successfully written into the thinned SC-SCF through the phase mask side-illumination method and two resonant dips were observed in the transmission spectrum. The transmission spectra and RI response characteristics of the device were theoretically analyzed and simulated based on the modal interference theory through finite element method. The RI and temperature responses of the device were experimentally investigated, respectively. The measured RI sensitivity and temperature sensitivity of one of the interference fringe dips were 504.1 nm/RIU for RI in range of 1.335∼1.345 and −10.1 pm/°C, respectively. The main Bragg grating dip was found to be insensitive to RI and have a temperature sensitivity of 12.3 pm/°C. This device is attractive for temperature-compensated RI sensing applications.

Supermode Bragg grating inscribed in a strongly coupled seven-core fiber and its responses to temperature and curvature

Xian Dong, You-Hang Xie, Jia-Le Ou, Chuang Wu, Jie Li, and Bai-Ou Guan
Opt. Express 31(2) 3258-3268 (2023)

Etched multicore fiber Bragg gratings for refractive index sensing with temperature in-line compensation

Wenbin Hu, Chi Li, Shu Cheng, Farhan Mumtaz, Cheng Du, and Minghong Yang
OSA Continuum 3(4) 1058-1067 (2020)

Supermode Bragg grating combined Mach-Zehnder interferometer for temperature-strain discrimination

Zhifang Wu, Hailiang Zhang, Perry Ping Shum, Xuguang Shao, Tianye Huang, Ying Ming Seow, Yan-ge Liu, Huifeng Wei, and Zhi Wang
Opt. Express 23(26) 33001-33007 (2015)

Sensor based on macrobent fiber Bragg grating structure for simultaneous measurement of refractive index and temperature

Tiegen Liu, Yaofei Chen, Qun Han, Fangchao Liu, and Yunzhi Yao
Appl. Opt. 55(4) 791-795 (2016)

Simultaneous measurement of refractive index and temperature with high sensitivity based on a multipath fiber Mach–Zehnder interferometer

Yajun Jiang, Tao Wang, Chi Liu, Dingyi Feng, Biqiang Jiang, Dexing Yang, and Jianlin Zhao
Appl. Opt. 58(15) 4085-4090 (2019)