Strain, torsion and refractive index sensors based on helical long period fibre grating inscribed in small-core fibre for structural condition monitoring

Cailing Fu, Yi Qing Ni, Tong Sun, Yiping Wang, Siqi Ding, Miodrag Vidakovic

Research output: Journal article publicationJournal articleAcademic researchpeer-review


This study is intended to develop long period fibre grating sensors for potential applications in environmental and durability monitoring of coastal structures. High-quality helical long period fibre gratings (HLPFGs) are inscribed in different types of small-core single mode fibre (SMF) by use of hydrogen-oxygen flame heating technique. A detailed investigation of the effect of core diameter on their transmission spectrum and optimum length of the HLPFG has been pursued. A longer length is required to achieve the same coupling attenuation in a smaller-core SMF than that of a larger-core fibre. The strain, torsion and refractive index (RI) properties of the HLPFG is investigated experimentally to develop a high-sensitivity sensor. The experimental results show that the strain sensitivity could be enhanced by means of employing a larger-core diameter SMF. Moreover, the HLFPGs are also sensitive to the torsion and external RI. Hence, such HLFPGs have great potential for sensing applications.

Original languageEnglish
JournalAdvances in Structural Engineering
Publication statusAccepted/In press - 2021


  • coastal structures
  • Fibre optic components
  • fibre optic sensors
  • helical long period fibre gratings
  • structural health monitoring

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction

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