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

L. Y. Shao; M. J. Yin; H. Y. Tam; J. Albert

doi:10.1117/12.974898

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7 November 2012 Fiber optic pH sensor with self-assembled multilayer nanocoatings on tilted FBG

L. Y. Shao, M. J. Yin, H. Y. Tam, J. Albert

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Proceedings Volume 8421, OFS2012 22nd International Conference on Optical Fiber Sensors; 84216A (2012) https://doi.org/10.1117/12.974898
Event: OFS2012 22nd International Conference on Optical Fiber Sensor, 2012, Beijing, China

Abstract

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)

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L. Y. Shao, M. J. Yin, H. Y. Tam, and J. Albert "Fiber optic pH sensor with self-assembled multilayer nanocoatings on tilted FBG", Proc. SPIE 8421, OFS2012 22nd International Conference on Optical Fiber Sensors, 84216A (7 November 2012); https://doi.org/10.1117/12.974898

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