Single weakly tilted FBG in 2-μm band capable of measuring temperature, axial strain, and surrounding refractive index

Dan Cheng, Fengping Yan, Ting Feng, Zhuoya Bai, Luna Zhang, Wei Wang, Shuo Liu, Hong Zhou, Yafei Hou

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Optical fiber devices and applications in the 2-μm band have been investigated extensively due to its unique advantages, such as eye safety. A fiber sensor based on tilted fiber Bragg grating with a grating plane angle of 2 deg is fabricated and experimentally tested. To the best of the authors' knowledge, this is the first tilted fiber Bragg grating sensor to realize simultaneous measurements of temperature, axial strain, and a certain range of surrounding refractive index (SRI) at the 2-μm band. This paper uses the wavelength detection method and selects three independent resonant wavelengths as the investigated parameters. Results show that perturbations of temperature, axial strain, and SRI can shift the wavelengths of the core mode resonance and cladding mode resonance to some degree. The temperature sensitivities of the core mode and cladding mode are nearly the same, but their axial-strain sensitivities are different. Furthermore, the core mode is insensitive to the change in SRI. The sensitivities of SRI, temperature, and strain can thus be obtained by experimentally determining the wavelength shifts of the three independent resonance peaks. A 3 × 3 matrix containing the relationship coefficients between the disturbances of temperature, axial strain, and SRI and wavelength shifts is constructed. By reversely solving the matrix equation, variations in temperature, strain, and SRI can be obtained using the experimental determination of wavelength drifts.

Original languageEnglish
Article number096107
JournalOptical Engineering
Issue number9
Publication statusPublished - Sept 1 2018


  • 2- μ m band
  • fiber-optic sensors
  • tilted fiber Bragg grating

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering(all)


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