掺镱双包层光纤激光器的自脉冲分析

Analysis of the Self Pulsing Behavior of Yb^3+-Doped Double Clad Fiber Laser

利用速率方程对掺Yb3+双包层光纤激光器的自脉冲行为进行了系统的理论研究,给出了光子数密度扰动时变关系式。数值模拟了光子数密度随时间及泵浦功率的变化;阻尼系数与后腔镜的反射率和掺杂粒子浓度的关系;以及光纤本身固有振荡频率随后腔镜反射率的变化。结果发现,增加输出端的反馈和粒子的浓度可以抑制自脉冲现象。当后腔镜的反射率大于0.7时,可以抑制光纤本身固有的振荡,并提出抑制光纤激光器自脉冲的措施。为设计掺Yb3+双包层光纤激光器提供了理论依据。

Based on the rate equations, the self-pulsing behavior ofyb3＋-doped fiber laser is studied theoretically. The expressions indicating the photon population density perturbations with time in yb3＋-doped fiber laser are given. The relationship between photon population density and time and different pump powers, the relationship between damping coefficient and different values of output coupling refiectivity and doping particle concentration, and the variation of the inherent oscillation frequency with different output coupling reflectivity are simulated. The results show that increasing the output end feedback or doping concentration will suppress self pulsing phenomenon. The inherent oscillation of fiber itself can be suppressed when the reflectivity of rear-cavity mirror is more than 0.7. Furthermore the measure to suppress self pulsing behavior of fiber laser is proposed. These will provide theoretical basis for the design of Yb3＋-doped fiber laser.