Fiber optic refractometric sensors using a semi-ellipsoidal sensing element

Martinez, Amalia Nallely Castro; Komanec, Matěj; Nemecek, Tomas; Zvánovec, Stanislav; Khotiaintsev, S.

doi:10.1364/ao.55.002574

Cited by 3 publications

(1 citation statement)

References 18 publications

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“…Here, we propose a device which does not include any additional element different from the pristine optical fiber itself to work as a label-free biosensor; this means that there is not any post-processing of the standard telecom fiber appart from the chemical functionalization. A U-shaped section of fiber and a semi-ellipsoidal section of fiber have been demonstrated to be feasible sensors [20,21]. In most of the works reported in the literature multimode fibers are used, whether microfibers [22], multimode fibers [23] or decladded fibers [24].…”

Section: Introductionmentioning

confidence: 99%

Resonant Couplings in U-Shaped Fibers for Biosensing

Londero¹,

Delgado-Pinar²,

Cuadrado-Laborde

et al. 2023

J. Lightwave Technol.

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U-shaped tight curvatures in optical fibers lead to resonant couplings between the fundamental and higher order modes that are sensible to different parameters, such as strain or temperature, for example. The optical response of the sensor consists on the shift of the resonant wavelength of the coupling. In the case of singlemode fibers, the coupling involves a so-called "cladding mode" and, due to its evanescent field, the curved region will be sensible to changes in the external medium, as well. In this paper, we present the fabrication and characterization of a robust, easy-to-make, U-shaped fiber sensor based on singlemode telecom fiber and its application for biosensing. The resonant nature of the sensing mechanism presents the advantage of large dynamic ranges for RI variations without the ambiguity of other techniques such as interferometry. We studied the performance of the U-shaped fiber sensor for different bending radii, to optimize its sensitivity and detection limit at 1550 nm operation wavelength, as well as the effect of temperature on its response. The shift of the resonant wavelength was measured in detail as a function of the external RI within the range [1.33-1,37]; the detection limit was established in (3.71±0.03)×10 -5 RIU. Furthermore, the device was successfully tested as a proof of concept biosensor, using a system model antigen-antibody (BSA-aBSA.)

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