Fiber-optic pressure sensor based on π-phase-shifted fiber Bragg grating on side-hole fiber

Qi Zhang, Nan Liu, Thomas Fink, Hong Li, Wei Peng, Ming Han

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


We present a fiber-optic pressure sensor based on a π-phase-shifted fiber Bragg grating (π FBG) fabricated on a side-hole fiber. Due to the resonance effect of a πFBG, its reflection spectrum features two notches that are dramatically narrower than the linewidth of a regular FBG of similar length. The narrow spectral notches allow high-resolution measurement of their spectral separation, significantly improving the pressure detection limit (defined herein as the minimum detectable pressure change) compared to sensors based on a regular FBG of a similar length and on the same fiber. The π FBG demonstrated in this letter is 8.3 mm long and the linewidth of each spectral notch is only 3.6 pm, corresponding to a quality factor of 4.3 × 10 5. The spectral notch separation exhibited a sensitivity of 20 pm/kpsi to pressure, which was limited by the geometry of the fiber holes, and little sensitivity to temperature. The Bragg wavelength shift exhibited a sensitivity of 11.4 pm/°C to temperature. In practice, a spectral resolution of 0.028 pm can be easily achieved for the πFBG demonstrated in this letter, leading to a pressure detection limit of 1.4 psi and a temperature detection limit of 0.0025°C.

Original languageEnglish (US)
Article number6257419
Pages (from-to)1519-1522
Number of pages4
JournalIEEE Photonics Technology Letters
Issue number17
StatePublished - 2012


  • fiber Bragg grating (FBG)
  • microstructure fiber
  • optical fiber sensor
  • pressure measurement
  • π-phase-shifted fiber Bragg grating (πFBG)

ASJC Scopus subject areas

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


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