Calculation of ytterbium-doped double-cladding CW fiber amplifiers
With 4th-order Runge-kutta method and relaxation method, we obtain the power distribution of pump light and signal light along fiber by solving the steady-state rate equations in ytterbium-doped double-cladding fiber amplifier. The relationships between the output power and the fiber length are discussed with different pump power and different doped concentrations of the fiber. The change of the output power versus the pump power is calculated. The power distribution along fiber and the relationship between output power and input power are analyzed when the signal is injected from z=L and z=0 respectively.