Abstract

SALCEDA-DELGADO, G. et al. Reconfigurable optical fiber Fabry-Perot interferometer and its applications for displacement sensing. Rev. mex. fis. [online]. 2022, vol.68, n.2, e021301.  Epub Mar 27, 2023. ISSN 0035-001X.  https://doi.org/10.31349/revmexfis.68.021301.

We report on a functional Fabry-Perot mode interferometer and its application for absolute displacement sensing. The proposed device consists of two well-cleaved tips of standard optical fibers that were introduced into a microcapillary glass with an inner diameter of ∼ 125.5 um; one tip was stuck to the capillary by the application of an electric arc from a standard splice machine, while the other tip was free to be longitudinally moved. The transmission spectrum of the interferometric device exhibited an interferometric pattern due to the reflections of the fundamental mode on the two partial reflecting tip surfaces of the standard optical fibers. The period and the intensity level of the interference pattern depend strongly on the separation between the optical fiber tips caused by the displacement of the free optical fiber tip. This dependence allows for the use of either period or intensity changes for length displacement sensing interrogation. For the period interrogation, the length can be accurately calculated and measured by taking the Fast Fourier Transform (FFT) of the detected interference pattern. For intensity interrogation, a simple photodetector can determine the distance that separates the optical fiber tips.

Keywords : Optical interferometry; optical fibers; optical device fabrication; optical sensors; optical fiber devices.

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