搭建了一个全光纤主振荡功率放大(MOPA)近衍射极限输出的超荧光源，线宽为亚纳米量级，最大输出功率为1509 W，输出斜率效率达到85.2%，光束质量因子稳定在M2=1.4。后向回光功率与输入功率呈线性关系，系统很好地抑制了受激布里渊散射(SBS)，并且对环境具有很好的抗干扰能力。在整个输出功率范围内，没有观察到自脉冲和弛豫振荡现象。

Core-diameter adjustment, in analogy to doping management, is proposed in this letter for balancing thermal load and nonlinear effects. In this scheme, the core-to-cladding ratio increases with increasing core diameter along the direction of signal and pump propagation. An all-fiber-integrated Yb-doped master oscillator power amplification (MOPA) is successfully demonstrated. Two segments of fiber with different core diameters but same inner-cladding diameters and doping levels are spliced together and used as gain fibers in the last stage. A maximum average output power of 200 W at an overall slope efficiency of 71% is achieved from the MOPA with a pulse energy of 2 mJ and peak power as high as 80 kW.

以被动调Q的固体薄片激光器作为种子光源，以中心波长976 nm的半导体激光器为抽运源，通过端面抽运耦合，搭建了窄脉宽双包层掺镱光纤放大器。实验研究了前向、后向端面抽运方式对窄脉宽双包层掺镱光纤放大器的输出平均功率、激光光谱、脉冲宽度等特性的影响，并进行分析讨论。结果表明,采用后向抽运方式，窄脉宽双包层掺镱光纤放大器，获得了平均功率为9.3 W的放大激光输出，重复频率为10 kHz，脉冲宽度为450 ps，峰值功率大于2 MW。

针对准分子激光器的相关应用，对准分子激光进行光谱控制是非常必要的。相关光谱控制主要包括激光线宽窄化及激光中心波长的稳定输出，常用的线宽压窄方式是利用扩束棱镜组结合光栅构成线宽压窄模块达到激光线宽窄化的效果。利用熔融石英(FS)等腰直角棱镜与光栅的组合实现了线宽0.957 pm的ArF准分子激光输出。理论分析和实验结果表明，作为深紫外波段的良好通光材料，熔融石英棱镜可以实现与常用氟化钙（CaF2）棱镜相近的线宽压窄结果。同时作为等腰直角方式设计，具有更高的切割成型工艺精度、更低的使用维护成本和更广泛的应用价值。

Theoretical simulation and experiments based on a prism beam expander and an echelle grating are conducted to study the dependence of linewidth and pulse energy on incidence angle and slit width. With a larger prism incident angle or narrower slit width, the linewidth becomes narrower while the laser pulse energy becomes lower. However, the pulse energy can be improved by optimally designing the prism beam expander. In addition, a subpicometer linewidth ArF laser is obtained with a double-prism beam expander and an echelle grating.

The maximum output power offiber lasers limited by the thermal degradation of double-clad fiber coatings is theoretically simulated. We investigated the thermal effects on high-power continuous wave (CW) fiber lasers with a focus on heating at the splice joints as well as on the doped fiber caused by quantum defects. Whether thermal interface materials are used or not, the thermal contact resistances between the fiber and its heat sink are measured separately while using different cooling equipments. Though the thermal management of splices is more difficult than that of active fibers, a temperature increase of 0.019 K/W is obtained for a splice joint into which the pump light launches. The splice joint sustains 3 kW of total passing power.

Array size scaling of passive coherent beam combination is explored theoretically. The Strehl ratio variation with wavelength is simulated in 4-, 9-, 16-, and 25-channel fiber arrays. The average Strehl ratio and phase error are calculated. The Strehl ratio is found to be near 100% for arrays with less than 5 fibers, but decreases significantly for larger arrays. These results are in good agreement with the recent experimental results.

利用二维4路光纤激光环形腔被动锁相相干组束实验平台，对被动相干组束系统的光束质量进行了研究。以衍射极限倍数β因子作为光束质量的评价方法，理论分析了光束占空比以及不同锁相模式对β因子的影响，实验测量了对应不同输出功率水平的β因子。结果表明，虽然β因子可以在一定程度上反映出不同实验条件下光束质量的差异，但是由于β因子的测量核心是确定出焦平面处83.8%环围能量（功率）比的桶尺寸，不能反映相干组束远场光斑的特点，不适合用于评价被动相干组束系统的光束质量。比较分析了β因子与光束质量，光束质量能更好地反映出相干组束的特点。