Photonic Sensors

, Volume 9, Issue 3, pp 197–204 | Cite as

A Novel High Sensitivity Refractive Index Sensor Based on Multi-Core Micro/Nano Fiber

  • Yuefeng Qi
  • Jin ZhangEmail author
  • Qi Feng
  • Xin Zhang
  • Yanyan Liu
  • Ying Han
Open Access
Regular 2018ACP Special Section


A refractive index sensor based on a multi-core micro/nano fiber is proposed for low refractive index solutions. At first, the mode field distribution of the tapered multi-core fiber is analyzed with the finite element model (FEM). After that, the relationship between the refractive index sensitivity and the diameter of the multi-core micro/nano fiber is calculated. At last, four sensors with different sizes are explored, and when the taper length is 16.20 mm, the refractive index sensitivity of the sensor can reach 5815.50 nm/RIU, which agrees with the theoretical analysis. The refractive index measurement error is less than 0.5‰, which has a high practical application value. The longer the taper length is, the smaller the fiber diameter is. According to the theoretical analysis, when the fiber diameter is less than 4.864 µm, the structure sensor’s refractive index sensitivity is higher than 10000 nm/RIU. At the same time, when the sensor’s taper length is 15.99 mm, its temperature sensitivity is −0.1084 nm/°C. Compared with single-mode fiber, the sensor proposed here has the advantages of stability, compact structure, and high sensitivity, which has a potential in the field of seawater salinity measurement.


Fiber optic sensor refractive index measurement multi-core fiber 



I want to thank everyone who helped me during the writing of this paper. I am very grateful to all the researchers in the paper, who worked hard to complete the research work of this paper. I would also like to especially thank the reviewers and editors of the journal for asking me for guidance and advice to make the paper more complete. This work was supported by the National Natural Science Foundation of China (Grant Nos. 61735011 and 61405173), the Hebei Province Natural Science Foundation of China (Grant Nos. F2016203389 and C2015003053), the Natural Science Foundation of the Xinjiang Uygur Autonomous Region (Grant No. 2018D01A25), and the Project Supported by Science and Technology Program of Hebei Province for Institutions of Higher Education (Grant No. ZD2017082).


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© The Author(s) 2019

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  • Yuefeng Qi
    • 1
    • 2
  • Jin Zhang
    • 1
    Email author
  • Qi Feng
    • 1
  • Xin Zhang
    • 1
  • Yanyan Liu
    • 1
    • 3
  • Ying Han
    • 1
    • 2
  1. 1.School of Information Science and EngineeringYanshan UniversityQinhuangdaoChina
  2. 2.Key Laboratory for Special Fiber and Fiber Sensor of Hebei ProvinceQinhuangdaoChina
  3. 3.BaYin GuoLeng Vocational and Technical CollegeKorlaChina

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