Fiber optic pH sensor with self-assembled multilayer nanocoatings on tilted FBG

L. Y. Shao, M. J. Yin, Hwa Yaw Tam, J. Albert

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

1 Citation (Scopus)


A novel fiber optic pH sensor is experimentally demonstrated by coating multilayers of poly(acrylic acid) (PAA) and poly(diallyldimethylammonium chloride) (PDDA) on a tilted fiber Bragg grating (TFBG) with the layer-by-layer (LbL) electrostatic self-assembly method. The utilization of PDDA/PAA pH sensitive polymeric coating presents a variation of the thickness with the pH of the solution, which introduces the wavelength shift and transmission change in the spectrum of TFBG. Using fast Fourier transform (FFT) analysis on a selected bandwidth of the transmission spectrum, it is found that the peak amplitude of the dominant spectral fringes increases with the increasing pH value with an near-linear sensitivity of 117 arbitrary unit (a.u.)/pH unit (in the range of pH 4.66 to pH 6.02). The dynamic response of the sensor also has been studied (10 s rise time and 18 s fall time).
Original languageEnglish
Title of host publication22nd International Conference on Optical Fiber Sensors
Publication statusPublished - 1 Dec 2012
Event22nd International Conference on Optical Fiber Sensors - Beijing, China
Duration: 15 Oct 201219 Oct 2012


Conference22nd International Conference on Optical Fiber Sensors


  • Fourier transform
  • Layer by layer
  • pH sensor
  • Polymeric coatings
  • Self-assembly
  • Tilted fiber Bragg grating

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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