Combined numerical model of laser rate equation and Ginzburg–Landau equation for ytterbium-doped fiber amplifier

We propose a combined model of the laser rate equation and the Ginzburg-Landau equation for simulation of the amplification of the ultrashort pulse in an ytterbium-doped fiber amplifier. An iterative procedure is designed for the repetition rate pulse sequence. The combined numerical model is compared with the pure dynamic rate equation for the amplification of a nanosecond single frequency pulse where both models are applicable. Good agreement is achieved. The combined model is then applied for the amplification of high repetition rate chirped pulse amplification in ytterbium-doped single-mode fiber. The slope efficiency, the wavelength shift, and the output spectrum width at different repetition rates are numerically investigated.