Guiseppe Cocito

Fluorine in MCVD optical fibers

Fluorine incorporation in silica glass network has been investigated using CCl 2 F 2 (Freon-12) as a source. Considerations on the stoichiometry of the reactions involved in CVD processes and experimental results on the refractive index are detailed. The data are collected in a ternary diagram that is proposed as a useful graphic representation in order to identify iso-index curves.

COST 218 evaluation of optical fiber lifetime models

More than 10 existing lifetime models for optical fibers, based on a power law to describe the stress-induced crack growth, are studied and compared. The number of models is reduced to only 1 basic model. This model is taking into account the effects of proof test. An alternative model, to be used when proof testing is performed on-line, is given as a worst-case limit of the basic model. A choice of 3 testing methods to obtain information about the weak-flaw distribution is given: dynamic-fatigue and variable screen-testing of long lengths or using the failure number during proof test. The models can also be used for titanium-doped fibers, but then a correction must be made for the compressive surface-stress. The lifetime models cannot be used for carbon-coated fibers and for fibers in water without further study.

Effect of YF3 and InF3 incorporation on ZBLALi glasses containing high levels of PbF2

Abstract The effects of YF 3 and InF 3 addition and substitution on ZrF 4 –BaF 2 –LaF 3 –AlF 3 –LiF (ZBLALi) glasses containing high levels of PbF 2 are systematically investigated in terms of glass characteristic temperatures, refractive indices, thermal expansion coefficients, viscosities and crystallization behavior. Based on thermal stability data, optimized glass compositions were deduced, which could be used as core glasses to achieve high numerical aperture fluoride fibres.

Effect of the glass composition on the emission band of erbium-doped active fibers

The positive effect of widening the 1.5 micrometers Erbium fluorescence band provided by alumina on germanosilicate core glass of active fibers is partially obtained also in magnesia silica host, but to a lesser extent, while zirconia silica fibers do not exhibit modification of the emission band. Excited state lifetimes, absorption, shape, and width of the band in different glass hosts were measured with the aim to optimize the core glass composition.