Refractometer With Etched Chirped Fiber Bragg Grating Fabry-Perot Interferometer in Multicore Fiber

Sema Guvenc Kilic, Yupeng Zhu, Qiwen Sheng, Mehmet Naci Inci, Ming Han

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


We report a sensitive and mechanically robust fiber-optic refractometer with temperature compensation based on a Fabry-Perot interferometer formed by two chirped fiber Bragg gratings on a seven-core multicore fiber. A small part of the fiber cladding at the sensing region is etched to expose the outer cores to the environment. While the optical modes supported by the outer cores are affected by both temperature and refractive index (RI) changes of the surrounding liquid, the optical mode in the central core of the fiber is affected by the temperature changes only. The wavelength shift due to the RI change is obtained by subtracting the wavelength shift of the central core from that of one of the outer cores so that the temperature effect is removed. The demodulation can also remove the errors caused by the wavelength drift of laser. Due to the narrow spectral features of the sensor, the sensor shows a low RI detection limit of 2.4 × 10-6 at a background RI of 1.316 at a wavelength of ∼1550 nm. Because only a small part of the cladding is removed, the sensor maintains excellent mechanical strength and stability.

Original languageEnglish (US)
Article number8648487
Pages (from-to)575-578
Number of pages4
JournalIEEE Photonics Technology Letters
Issue number8
StatePublished - Apr 15 2019


  • Fabry-Perot interferometers
  • Optical fiber sensors
  • fiber Bragg gratings
  • multicore fibers
  • refractometers

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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