Special optical fibers and fiber capillaries coated with Indium-Tin-Oxide

Indium-Tin-Oxide (ITO) is one of the most widely used transparent semiconductors due to its electrical conductivity and optical transparency. Thin layers of ITO are prepared in industrial scale by a range of physical deposition techniques such as magnetron sputtering, dip-coating method etc. The ITO thin films with tailored thickness from 220 nm to 550 nm were prepared by dip-coating method on planar substrates. The resistivity of prepared films was tailored from 2.5 Ω•m to 0.02 Ω•m by the annealing temperature. The deposition technology was adapted to the fiber optic substrates. ITO layers were successfully deposed on the decladded polymer coated silica fibers (PCS) and inside the capillary fibers. The resistivity of prepared optical fiber was below 0.15 MΩ•m-1. Prepared films appeared values of the refractive index around 1.458. The strong dependence of the resistivity of prepared ITO films on the humidity was found. The reason could be found in the relatively high porosity of prepared ITO film which supports the adsorption of the water to the grain boundaries of ITO nanocrystals.