Capillary optical fibers based on SiO2 -TiO2-P2O5 and TiO2-P2O5 internal coatings prepared by sol-gel method

This paper presents a novel approach to the preparation of capillary optical fibers using sol-gel method. It employs a novel modification of sol-gel techniques for the application of layers onto the inner walls of silica tubes. This modification was employed for the preparation of multilayer internal coatings of silica tubes which consist of alternating low-index layers of silica and high-index layers containing titania. Novel materials, namely silica-titania-phosphorus pentoxide and titania-phosphorus pentoxide prepared by the sol-gel method, were used in the high-index layers. Morphology and optical properties of single layers of all the materials applied on glass slides are presented as well as the optical properties of multilayer coatings inside silica tubes. The internally coated tubes were drawn into fibers with air and solid cores. Characteristics of the prepared fibers are also shown in the paper. Fibers with optical losses below 0.02 dB/cm have been prepared. [Graphics] .

Automated summary

This paper presents a new approach to preparing capillary optical fibers using sol-gel method. A novel modification of sol-gel techniques is employed for applying layers onto the inner walls of silica tubes. Multilayer internal coatings with alternating low-index silica layers and high-index titania layers are prepared using novel materials prepared by sol-gel method. Morphology and optical properties of single layers and multilayer coatings are studied, and fibers with low optical losses below 0.02 dB/cm are successfully prepared.