Abstract

In this article a Vernier effect based sensor is analyzed and demonstrated experimentally in a tri-microfiber coupler (Tri-MFC) and polarization-maintaining fiber (PMF) loop interferometer (Tri-MFC-PMF) to provide ultrasensitive refractive index and temperature sensing. The main novelty of this work is an analysis of parameters of the proposed Tri-MFC-PMF with the objective of determining the conditions leading to a “strong” Vernier effect. It has been identified by simulation that the Vernier effect is a primary factor in the design of Tri-MFC-PMF loop sensing structure for sensitivity enhancement. It is furthermore demonstrated experimentally that enhancing the visibility of the Vernier spectrum in the Tri-MFC-PMF allows to achieve an ultrahigh refractive index and temperature sensitivity with improved measurement accuracy. Specifically it is shown that small values of the total phase difference (π/16+Nπ)∼(π/4+Nπ), where N is an integer, accumulated over the PMF loop and Tri-MFC loop result in a “strong” Vernier effect. Experimentally an ultrahigh refractive index sensitivity of -20588 nm/RIU and temperature sensitivity of 0.019 nm/°C are demonstrated by utilizing the stronger Vernier effect with “clear” Vernier spectrum. This analysis of the parameters may be useful to future researchers seeking to increase the measurement accuracy of sensors by enhancing the spectral visibility of the Vernier effect in other types of fiber optic interferometers.

Combined-Vernier effect based on hybrid fiber interferometers for ultrasensitive temperature and refractive index sensing

Zejun Jiang, Fugen Wu, Jun Yang, Kunhua Wen, Pengbai Xu, Zhangjun Yu, Jiangquan Sun, Yuncai Wang, and Yuwen Qin
Opt. Express 30(6) 9578-9589 (2022)

Ultrasensitive temperature sensor with Vernier-effect improved fiber Michelson interferometer

Yuanfang Zhao, Maolin Dai, Zhenmin Chen, Xuanyi Liu, M. S. Aruna Gandhi, Qian Li, and H. Y. Fu
Opt. Express 29(2) 1090-1101 (2021)

Ultrasensitive refractive index sensor based on enhanced Vernier effect through cascaded fiber core-offset pairs

Jiewen Li, Meng Zhang, Minggui Wan, Chunli Lin, Shihong Huang, Cuihong Liu, Qingping He, Xiaozhong Qiu, and Xiaohui Fang
Opt. Express 28(3) 4145-4155 (2020)

Temperature-compensated magnetic field sensing with a dual-ring structure consisting of microfiber coupler-Sagnac loop and fiber Bragg grating-assisted resonant cavity

Fangfang Wei, Dejun Liu, Arun Kumar Mallik, Gerald Farrell, Qiang Wu, Gang-Ding Peng, and Yuliya Semenova
Appl. Opt. 58(9) 2334-2339 (2019)

Ultrasensitive refractive index fiber sensor based on high-order harmonic Vernier effect and a cascaded FPI

Haiming Qiu, Jiajun Tian, and Yong Yao
Opt. Express 31(8) 13053-13064 (2023)