Analytical Formulation of an Yb-doped Tandem-Pumping Fiber Amplifier

An analytical formulation of a multi-kilowatt ytterbium-doped double-cladding tandem-pumped fiber amplifier was developed and is reported in this paper. The model consists of a system including the laser rate, pumping and seed power equations. The model was validated by describing a fiber amplifier behavior with a 5.986kW, 1018nm pumping and a signal seed of 75W, 1080nm, yielding a maximum power output of 5.448kW, with an efficiency of 91.1%. The thermal equations are solved for the temperature distribution along the fiber with a maximum temperature of 43.24°C, when the convective coefficient of 4000W. m-2. K
⁻¹
is used.