Temperature-Insensitive Refractometer Based on a Wave-Shaped Fiber Modal Interferometer Using No-Core Fiber

Taeyoon Kim, Junha Jung, Jinho Lee, Geun Weon Lim, Ju Han Lee

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We propose a novel, temperature-insensitive fiber optic sensor for refractive index (RI) measurement. Our refractometer is based on multimodal interference in a wave-shaped configuration with localized reverse curvature, which is composed of a concatenating standard single-mode fiber (SMF)-no-core fiber (NCF)-SMF structure. The wave-shaped fiber optic refractometer is composed of an SMF-NCF-SMF combination, in which the length of the NCF located at the top of the structure, is only 4 mm. The main wave-shaped fiber has a curvature of 20 m-1, while the wave-shaped NCF section has a curvature of -0.0055 m-1. The NCF section with no polymer coating, which acts as a sensing head, is modified to have a curvature opposite to the curvature of the whole wave-shaped optical fiber, by applying localized external pressure. The RI measurement sensitivity of our proposed refractometer was estimated at approximately -53.24 nm/RIU, while its temperature sensitivity was 0 pm/°C.

Original languageEnglish
Article number9415743
Pages (from-to)16066-16077
Number of pages12
JournalIEEE Sensors Journal
Issue number14
StatePublished - 15 Jul 2021


  • Optical fiber sensors
  • multimodal Interference
  • refractive index measurement
  • temperature insensitive


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