高能量脉冲光纤激光器荧光特性  被引量:1

Analysis of Fluorescence Characteristic in High-energy Pulsed Fiber Laser

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作  者:赵羽[1] 赵德双[2] 刘永智[1] 

机构地区:[1]电子科技大学光电信息学院,四川成都610054 [2]电子科技大学物理电子学院,四川成都610054

出  处:《发光学报》2008年第5期891-896,共6页Chinese Journal of Luminescence

基  金:国家自然科学基金(60736038);国防预研基金(9140A02040106DZ0222)资助项目

摘  要:高能量脉冲激光器中,高强度的抽运光注入掺杂光纤后会部分转化为荧光,导致抽运效率的降低。基于铒掺杂光纤中铒离子的能级结构,分析了高能量脉冲光纤激光器中荧光的产生机理,采用非线性薛定谔(Nonlinear Schrdinger)方程和能级跃迁模型的速率方程,建立了高能量脉冲光纤激光器中荧光和抽运光的传输模型。通过此模型进行了数值仿真研究,首次深入分析了抽运光和荧光功率沿光纤轴向分布的变化规律,研究了荧光功率、抽运效率与光纤掺杂浓度的关系,并得出了抑制荧光产生、提高抽运效率的方法。数值结果表明:在铒掺杂光纤中,荧光和抽运光分别沿光纤的轴向近似呈指数规律衰减,且荧光的衰减速度比抽运光快;当抽运光功率一定时,铒掺杂光纤在980nm激光抽运下产生的荧光功率比1480nm激光抽运下的低,且980nm激光抽运下产生荧光的阈值比1480nm的高;抽运光功率一定时,铒掺杂光纤中产生的荧光功率随其掺杂浓度的增加而增加,而抽运效率随着掺杂浓度的增加而降低;衰减系数一定时,荧光沿掺铒光纤轴向的衰减速度随增益系数的增加而增加。理论分析的结论与参考文献中的实验结果吻合得很好。因此,为有效抑制荧光产生、提高抽运效率,应选择980nm的激光作为抽运光源,并在激光器的增益一定时尽量降低光纤的掺杂浓度,或者在一定的掺杂浓度下尽量提高增益系数。The emission of fluorescence in the high-energy pulsed fiber laser will reduce pump efficiency when high energy pump power is injected into doped fiber. The emission mechanism of the fluorescence in high energy pulsed fiber laser was analyzed based on the level model of Er^3 + doped fiber (EDF). To explore fluorescence characteristic and improve the pump efficiency of high-energy pulsed fiber laser, a novel stimula-tion model is developed by combining the rate (NLS) equation. With the proposed mode and equation of Er^3+ doped fiber laser and nonlinear Schrodinger numerical method, we have made an investigation on the longitudinal propagation characteristics of pump light and fluorescence, and on the relationship among the fluorescence power, the pump efficiency and Er^3+ doping concentration. The numerical results show us that the pump and fluorescence power would decrease exponeptially along the longitudinal axis of Er^3 + doped fiber and the fluorescence power decrease faster than that of the pump power. The fiber laser would emit less fluorescence when pumped by 980 nm laser than that pumped by 1 480 nm laser. The results also show that when the pump power is certain, the power of fluorescence emitting in the EDF would increase as the doped density does, and the pump efficiency would decrease as the doped density increase. When the attenuation coefficient is certain, the fluorescence power would attenuate faster when the gain coefficient increases. Comparing with the previous work, we found that the results given by the proposed model are in good agreement with experimental results in the references. Therefore, in order to effectively depress the fluorescence and improve the pump efficiency, pump laser with the center wavelength of 980nm is suggested to be chosen, and the doped density should be decreased as much as possible when the gain is certain, or the gain should be increased as much as possible when the doped density is certain.

关 键 词:铒掺杂光纤 荧光 激发态吸收(ESA) 速率方程 非线性薛定谔方程 

分 类 号:O482.31[理学—固体物理] TN253[理学—物理]

 

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