A mathematical model of optical breakdown of an optical fiber core

Abstract

This article describes a mathematical model of an optical fiber core breakdown based on the thermal conductivity equation. The problem is solved in an axisymmetric formulation. The computational domain consists of four elements with different thermophysical properties at the boundaries of which conjugation conditions are fulfilled. The term describing a heat source in the model is defined by a radiation wavelength and refraction indexes of the core and the shell. It also includes absorption coefficient showing the absorption of radiation resulting from electron release due to the thermal ionization of a Ge-doped silica core. The distributions of temperature fields in optical fiber are obtained. The temperature field propagation velocity is estimated. Based on the calculations, it is possible to estimate the time of occurrence of optical breakdown for different wavelengths of radiation introduced into the fiber.