Modeling of Glass Flow during Arc Fusion Splicing of Fiber Optic Filaments.

An analytical model is developed for the arc fusion splicing of high silica fiber optic filaments. A one-dimensional transient heat transfer physical model is developed from energy balance considerations to determine the temperature distribution of the fiber. Electric discharge heating is modeled empirically. Physical properties of the silica fiber optic material are modeled as functions of temperature. A two-dimensional physical model of viscoelastic glass flow is developed from force balance considerations and includes deformation due to thermal, viscous and elastic strain. Maxwell stress-strain relationships are assumed. Finite difference numerical algorithms are derived for an Lagrangian viewpoint. Simultaneous equations for heat transfer are solved implicitly in a tri-diagonal matrix routine. Simultaneous equations for viscoelastic flow are solved by back substitution techniques that account for boundary condition transitions upon gap closure. Experiments were conducted using a commercial arc fusion splicer to provide experimental verification of the analytical model. Evolution of the fiber distortion was photographically recorded for repeated heating cycles of a continuous element and a free end respectively. The geometric distortion of the element with time was compared to predictions obtained with the analytical model.