Lossy-mode resonance-based refractometers by means of indium oxide coatings fabricated onto optical fibers

Abstract

In this work, lossy mode resonance (LMR) based optical fiber refractometers are fabricated by using a transparent coating (indium oxide), as the LMR supporting layer. The utilization of indium oxide coatings permits the fabrication of highly sensitive optical fiber refractometers and enables the tunability of the LMR by adjusting the fabrication parameters, such as the coating thickness. The detection technique is based on the wavelength shift of the LMR. In this work it has been studied the influence of the external refractive index, achieving a maximum sensitivity of 2.24e-4 refractive index units per nanometer. Moreover, by adequated parameterization, more than one LMR can be observed in the wavelength range analyzed in the experiments, which leads to a more accurate measurement of the refractive index.