Bragg Gratings in Two-Core Rectangular Fiber for Discrimination of Curvature, Strain, and Temperature Measurements

Lin Htein, Dinusha Serandi Gunawardena, Chern Yang Leong, Hwa Yaw Tam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)


We report, for the first time, the development of a rectangular fiber with two cores consisting of different refractive indices for the discrimination of temperature effects during strain or curvature measurements using fiber Bragg gratings written in a single segment of fiber. Two cores with a diameter of 8~\mu \text{m} and a rectangular cladding with dimensions of 120\,\,\mu \text{m} \times 255\,\,\mu \text{m} permit convenient splicing to conventional single-mode fiber and support easy identification of the orientation of the fiber. When placed in the desired orientation, each core of the two-core rectangular fiber experiences a different spectral shift in the presence of applied strain or curvature. The sensitivities of the two cores are 0.87 and 1.08 pm/ \mu \varepsilon for strain, 126 and -128 pm/m-1 for curvature, and 10.05 and 10.40 pm/°C for temperature, respectively. In addition, the flat cladding structure of the fiber provides a large physical contact area between the sensing fiber and the substrate than a circular fiber and allows better strain coupling between the object and the fiber.

Original languageEnglish
Article number9247138
JournalIEEE Transactions on Instrumentation and Measurement
Publication statusPublished - 3 Nov 2020


  • Bragg gratings
  • curvature
  • flat cladding
  • rectangular fiber
  • sensor
  • strain
  • temperature

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering

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