1.54μmEr^(3+),Yb^(3+)共掺玻璃激光器的速率方程及数值分析

Rate equations and numerical analysis on 1.54μm Er^(3+),Yb^(3+) co-doped glass laser

LD抽运共掺Er,Yb玻璃激光器中的跃迁过程较复杂 ,针对双掺离子之间的能量传递和Er3 +的多种跃迁过程 ,给出了详细的准三能级系统的速率方程 ,在合理简化后进行了数值分析 ,分析了Er3 +掺杂浓度和介质长度、抽运光斑、输出镜透过率、谐振腔长、抽运光的椭圆度等因素对激光阈值及斜率效率的影响 .

Transitions of LD pumped Er 3+,Yb 3+ co-doped glass laser are rather complicated. Considering energy transfer between Er 3+ and Yb 3+, cross-relaxation, upconversion luminescence and other transition processes, rate equations of quasi-three energy-level-system of the Er 3+,Yb 3+ co-doped laser is presented and useful conclusions are drawn by numerical analysis in the paper. The optimal Er 3+ concentration is 0 3%—1 0%(corresponding ot (3—10)×10 25/m 3) and media length 1—0 5mm(The length is shorter with higher Er 3+ concentration). The pump laser waist in the media should be close (equivalent is the best) to the oscillating laser waist so that the pumping threshold is low and slope efficiency high. With smaller pumping waist (less than 50 μm is better), the threshold is lower. The optimal transmission of output coupler is about 1%. A shorter cavity length can make the threshold smaller. As to the LD emitted ellipse beam, it is better to round the pump beam so as to improve the slope efficiency.