Fiber Optic Sensors|2 Article(s)
Liquid modified photonic crystal fiber for simultaneous temperature and strain measurement
Chupao Lin, Ying Wang, Yijian Huang, Changrui Liao, Zhiyong Bai, Maoxiang Hou, Zhengyong Li, and Yiping Wang
A liquid modified photonic crystal fiber (PCF) integrated with an embedded directional coupler and multi-mode interferometer is fabricated by infiltrating three adjacent air holes of the innermost layer with standard 1.48 refractive index liquids. The refractive index of the filled liquid is higher than that of background silica, which can not only support the transmitting rod modes but also the “liquid modified core” modes propagating between the PCF core and the liquid rods. Hence, the light propagating in the liquid modified core can be efficiently coupled into the satellite waveguides under the phase-matching conditions, resulting in a dramatic decrease of the resonant wavelength intensity. Furthermore, there is a multi-mode interference produced by modified core modes and rod modes. Such a compact (~0.91 cm) device integrated with an embedded coupler and interferometer is demonstrated for high-sensitivity simultaneous temperature (~14.72 nm/°C) and strain (~13.01 pm/μ ) measurement.
Photonics Research
  • Publication Date: Mar. 06, 2017
  • Vol. 5, Issue 2, 02000129 (2017)
Sensing of microparticles based on a broadband ultrasmall microcavity in a freely suspended microfiber
Yang Yu, Ting-Hui Xiao, Hong-Lian Guo, and Zhi-Yuan Li
We theoretically design and experimentally realize a broadband ultrasmall microcavity for sensing a varying number of microparticles whose diameter is 2 μm in a freely suspended microfiber. The performance of the microcavity is predicted by the theory of one-dimensional photonic crystals and verified by the numerical simulation of finite-difference time domain and the experimental characterization of reflection and transmission spectra. A penetrating length into the reflectors as small as about four periods is demonstrated in the numerical simulation, giving rise to an ultrasmall effective mode volume that can increase the sensitivity and spatial resolution of sensing. Moreover, a reflection band as large as 150 nm from the reflectors of the microcavity has been realized in silica optical microfiber in the experiment, which highly expands the wavelength range of sensing. Our proposed microcavity integrated into a freely suspended optical fiber offers a convenient and stable method for long-distance sensing of microparticles without the need for complicated coupling systems and is free from the influence of substrates.
Photonics Research
  • Publication Date: Apr. 10, 2017
  • Vol. 5, Issue 3, 03000143 (2017)