Abstract

In this work, the characteristics of lossy mode resonances (LMRs) in double-clad fibers where the refractive index (RI) of the second cladding is lower than that of the first cladding are analyzed both numerically and experimentally. In the first place, the LMRs spectra obtained with a 75 nm TiO₂ thin film are simulated, and it is observed that a thicker second cladding improves the width of the resonances, making them narrower. Then, two experimental cases (no second cladding, and second cladding with thickness of 1.13 μm) are assessed, showing a good agreement with the previous simulations. Finally, an experimental refractometric study is carried out in liquids (surrounding medium refractive index in the 1.34 - 1.40 range) for both fibers, calculating the full width at 1 dB (FW_1dB), the sensitivity, and the figure of merit (FOM). The FW_1dB is better for the LMR obtained on the fiber with second cladding while the sensitivity is slightly greater for the fiber without second cladding. In the case of the FOM, it is higher for the double-clad fiber as the narrowing of the resonances outweighs the lower sensitivity. These results show that the performance of LMR-based optical fiber sensors can be improved by employing double-clad fibers.

High sensitive refractometers based on lossy mode resonances (LMRs) supported by ITO coated D-shaped optical fibers

P. Zubiate, C. R. Zamarreño, I. Del Villar, I. R. Matias, and F.J. Arregui
Opt. Express 23(6) 8045-8050 (2015)

Improving the width of lossy mode resonances in a reflection configuration D-shaped fiber by nanocoating laser ablation

Omar Fuentes, Patrizio Vaiano, Ignacio del Villar, Giuseppe Quero, Jesús Corres, Marco Consales, Ignacio Matías, and Andrea Cusano
Opt. Lett. 45(17) 4738-4741 (2020)

Theoretical and experimental research of lossy mode resonance-based high-sensitivity optical fiber refractive index sensors

Wan-Ming Zhao, Qi Wang, Xue-Zhou Wang, Xiang Li, Jian-Ying Jing, and Hong-Zhi Sun
J. Opt. Soc. Am. B 36(8) 2069-2078 (2019)

Twin lossy mode resonance on a single D-shaped optical fiber

J. J. Imas, C. R. Zamarreño, P. Zubiate, I. Del Villar, J. M. Pérez-Escudero, and I. R. Matías
Opt. Lett. 46(13) 3284-3287 (2021)

Beyond near-infrared lossy mode resonances with fluoride glass optical fiber

I. Vitoria, C. R. Zamarreño, A. Ozcariz, J. J. Imas, and I. R. Matias
Opt. Lett. 46(12) 2892-2895 (2021)