Numerical Modeling of Three-level System in Ytterbium-doped Photonic Crystal Fiber Laser

摘要

In order to investigate the power characteristics of the Yb-doped photonic crystal fiber(PCF) laser, we have represented a simple three-level system modeling based on a rate equation model. According to our theoretical modeling, the variation of the output power P_(out) via the pump power P_p is theoretically studied, which agrees well with experimental data. Then, we have investigated the effects of the doped concentration of Yb ions, the length and the effective mode field area of the PCF on the output power P_(out) of the Yb-doped PCF laser, respectively. The results show that the output power P_(out) first increases and then decreases when the doped concentration of Yb ions N_0 increases and when the pump power P_p and the length of the PCF L are constant. And the optimal doped concentration N_m exponentially decreases when the length L of the PCF increases and the slope of the optimal doped concentration N_m also decreases when the length L of the PCF increases. The output power P_(out) first increases and then decreases when the length of the PCF L increases and when the pump power P_p and the doped concentration N_0 are constant. And the optimal length L_m of the PCF exponentially decreases when the doped concentration N_0 increases and the slope of the length of the PCF also decreases when the doped concentration N_0 increases. The output power P_(out) linearly decreases when the effective mode field area A increases.