The Dynamic Characteristics of a Low Repetition Rate, High Energy Pulse Pumped Yb-doped Fibre Amplifier
T. Wei, Z-Y. Tan, J-F. Li and J-H Zhu
Some analysis of the dynamic characteristics of the Yb-doped fibre amplifier under pulsed pump are performed by solving a set of time-dependent rate and power transfer equations based on finite-difference method. The upper level population distribution, amplified spontaneous emission (ASE), the stored energy and the output pulse energy etc., are emphasized in this paper. The results show that, the amplification can be achieved that under continuous wave (CW) pump and the ASE can be restrained by choosing an optimum pump pulse width. In addition, decay of the stored energy is presented, the time interval between pump pulses is also determined. In the experiment the amplification results of the fibre amplifier are measured by tuning the width of pump pulse. The repetition rate can be set freely from single shot to 250 Hz. And the amplification characteristics are independent of the repetition rate. The experiment shows the validity of the numerical simulation.
Keywords: Fibre amplifier, pulsed pump, semiconductor laser, dynamic characteristic, numerical simulation