Additivity of the coefficient of thermal expansion in silicate optical fibers

A model that predicts the material additivity of the thermal expansion coefficient in the binary silicate glasses most commonly used for present (GeO₂-SiO₂, P₂O₅-SiO₂, B₂O₃-SiO₂, and Al₂O₃-SiO₂) and emerging (BaO-SiO₂) optical fibers is proposed. This model is based on a derivation of the expression for the coefficient of thermal expansion in isotropic solids, and gives direct insight on the parameters that govern its additivity in silicate glasses. Furthermore, a consideration of the local structural environment of the glass system is necessary to fully describe its additivity behavior in the investigated systems. This Letter is important for better characterizing and understanding of the impact of temperature and internal stresses on the behavior of optical fibers.