This paper experimentally analyses the axial strain sensitivity of gold-coated tilted fiber Bragg gratings immersed in liquid. For the polarization mode P (polarization parallel to the tilt plane), a strong attenuation of some cladding mode resonances appears in the transmitted spectrum due to the coupling with the Plasmon wave. When axially straining the grating, we report a unique behavior for the cladding mode resonance that presents the strongest attenuation. It presents an axial strain sensitivity (1.33 pm/με) higher than the Bragg wavelength (1.28 pm/με) and much higher than neighboring cladding modes (1.16 to 1.22 pm/με), meaning that differential strain measurements can be achieved with such a sensing platform.

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Keywords Fiber Bragg gratings, Gold coating, Mechanical strain, Optical fibers, Plasmonics, Sensors, Tilted gratings
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Conference 22nd International Conference on Optical Fiber Sensors
Voisin, V., Caucheteur, C., Mégret, P., & Albert, J. (2012). Enhanced axial strain sensitivity in plasmonic tilted fiber Bragg gratings sensors. Presented at the 22nd International Conference on Optical Fiber Sensors. doi:10.1117/12.970404