中文摘要：

实验研究了半导体激光器双端泵浦的掺铥双包层光纤激光器，获得了最大功率为4．72w的连续激光输出，在该输出功率下的中心波长为1997．6nm并且光谱范围较宽。实验中所采用两个半导体激光器泵浦源的最大入纤功率分别为11．48W和8．74w，对应中心波长分别为790．1nm和787．2nm。激光器斜率效率为33％。实验分析得出决定耦合系统耦合效率的主要环节是入纤过程中的损耗，包括光纤端面的不理想以及泵浦聚焦光斑与光纤不匹配。实验也证明影响功率提高的关键因素还在于输出端二色镜对激光的透过率和掺杂浓度一定下的增益光纤长度。

英文摘要：

Continuous-wave operation of a double-clad Tm--doped silica fiber laser with a wide spectral range centered at 1997.6 nm, pumped by two semiconductor lasers, yielded an output power of 4.72 W for 11.48 W and 8.74 W of launched pump power at 790.1 nm and 787.2 nm, respectively. The slope efficiency with respect to launched diode power was 33%. The imperfection of the fiber end face and the mismatch between the pump spot and fiber seriously decrease the coupling efficiency. The most two important factors to affect the laser output power are the laser transmissivity of the dichroic mirror at the output end and the length of the gain fiber at a certain doping concentration.