Research on testing the characteristics of hydrogel film by using a long-period fiber grating

Yu Xiujuan, Zhang Min, Childs Paul, Wang Liwei, Lei Ming, Liao Yanbiao, Ju Jian, Jin Win

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)


A method for testing the physical and optical properties of hydrogel thin films is reported based on using long-period fiber gratings. For humidity levels from 50% to 70% KH, a wavelength decrease of 11.0 nm is observed, with a sensitivity of 0.6nm/%RH. For humidity levels from 70% to 98% RH, a wavelength increase of 6.3nm is seen, with a sensitivity of 0.2nm/%RH. For humidity levels greater than 60% RH, the transmission loss at resonance increases rapidly, showing a high degree of sensitivity of 0.5dB/%RH. The blueshift of the wavelength was seen to be due to a thickening of the overlay, while the redshift of wavelength is due to the contribution of the drop in refractive index of the overlay. The results match well with what is expected theoretically.
Original languageEnglish
Pages (from-to)2171-2177
Number of pages7
JournalApplied Optics
Issue number11
Publication statusPublished - 10 Apr 2009

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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