Tip optical fiber refractive index sensor based on a thin copper film

Y. Lopez-Dieguez, J. M. Estudillo-Ayala, D. Jáuregui Vázquez, L. A. Herrera-Piad, J. A. Martín-Vela, J. M. Sierra-Hernandez, J. C. Hernandez-Garcia, M. Bianchetti, M. Avazpour, R. Rojas-Laguna



We report a refractive index tip fiber optic sensor based on a modal interferometer coated with a thin copper film. This device can be used for solute concentration in aqueous mixture measurement. The copper film increases the device reflectivity and, as a result, increases the multimodal interference pattern visibility. To validate the sensor device, different water-glycerol weight concentrations were used in the range from 0 to 45 Glycerol %. The recorded spectral responses show a redshifting, and a sensitivity of 19 pm / (Glycerol % by weight) from 0 to 18 % and 4.7 pm / (Glycerol % by weight) from 18 to 45 % was achieved. Besides, using a phase analysis we calculated a sensitivity of -15 rad/RIU.


Fiber optic sensor, Modal Fiber Optic Interferometer, Liquid Concentration Measurement

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