Theoretical and experimental investigation of spatial temperature distribution in active fiber under conditions of laser radiation generation

Abstract

The longitudinal and transversal temperature distribution in active waveguide, doped with Yb/Er ions, under conditions of laser generation was calculated as the composition of two mathematical models: computation of longitudinal pump radiation distribution by solution of rate equations for Yb/Er doped active medium and computation of transversal temperature distribution by solution of heat equation for convectively cooled fiber using finite element method. The theoretical results were in a good agreement with experimental data, measured by the piezoelectric resonators used as temperature sensors, placed on the surface of the fiber. The pump radiation transferring length in active waveguide and the location of the most heated fiber area, as well as the maximum temperature value, were calculated using a created model of pump radiation transferring into GT-wave active fiber.