9 June 2004 High-resolution refractive index sensor by using thinned fiber Bragg gratings
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Proceedings Volume 5502, Second European Workshop on Optical Fibre Sensors; (2004) https://doi.org/10.1117/12.566542
Event: Second European Workshop on Optical Fibre Sensors, 2004, Santander, Spain
Abstract
In this work, high sensitivity refractive index measurements have been experimentally demonstrated by using thinned fiber Bragg grating sensors. When cladding layer is reduced, significant changes in the effective refractive index occur due to external refractive index modifications, this means that consequent shifts in the Bragg wavelength are expected. Reduced cladding layer have been obtained by using wet chemical etching in hydrofluoric acid solutions. Experimental tests to prove sensor sensitivity induced by changes in the external refractive index have been carried out by using glycerine solutions with well known refractive indices. Obtained results agree with the numerical analysis carried out by using three layer fiber model. If the cladding layer is full etched resolutions of ≈10-5 and ≈10-4 for outer refractive index around 1.45 and 1.333, respectively, are possible. In addition, higher sensitivity and robustness could be achieved by using fiber Bragg grating sensors written in multimode graded index fibers as shown in a preliminary study here reported.
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A. Iadicicco, Andrea Cusano, Antonello Cutolo, Michele Giordano, "High-resolution refractive index sensor by using thinned fiber Bragg gratings", Proc. SPIE 5502, Second European Workshop on Optical Fibre Sensors, (9 June 2004); doi: 10.1117/12.566542; https://doi.org/10.1117/12.566542
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