Metal coating for enhancing the sensitivity of fibre Bragg grating sensors at cryogenic temperature

C. Lupi, F. Felli, L. Ippoliti, M.A. Caponero, M. Ciotti, V. Nardelli, A. Paolozzi

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Fibre Bragg grating (FBG) sensors that are immune to electromagnetic interference could advantageously perform cryogenic temperature monitoring in superconducting magnetic fields, but their intrinsic temperature sensitivity is quite poor and must be enhanced. In fact, the low thermal expansion coefficient of silica limits the temperature sensitivity of bare FBG sensors at cryogenic temperature. In this paper the possibility of improving the temperature sensitivity of FBG sensors by metal coating is investigated. Specifically, zinc and copper coating depositions are performed by the traditional electrowinning process, after aluminium pre-coating of the sensor. Coated FBG sensors are inspected by both optical and metallographic techniques. SEM metallographic investigations show that a homogeneous deposit is obtained, with good metal adhesion to the FBG sensor. Optical testing shows that the optical properties of the coated FBG sensors are slightly affected: aluminium pre-coating produces appreciable modification of the diffraction spectrum in both peak width and peak shift, while zinc coating produces a moderate peak shift and copper coating just enlarges the peak width. Results presented in this paper show that both metals appreciably increase the temperature sensitivity of the FBG sensors. Zinc coating provides the highest sensitivity and high-resolution temperature measurements are possible at temperatures as low as 15 K. © 2005 IOP Publishing Ltd.
Original languageEnglish
Pages (from-to)-
JournalSmart Materials and Structures
Issue number6
Publication statusPublished - 1 Dec 2005
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Civil and Structural Engineering
  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering

Cite this

Lupi, C., Felli, F., Ippoliti, L., Caponero, M. A., Ciotti, M., Nardelli, V., & Paolozzi, A. (2005). Metal coating for enhancing the sensitivity of fibre Bragg grating sensors at cryogenic temperature. Smart Materials and Structures, 14(6), -.