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。

以被动调Q的小型Nd:YAG/Cr4+:YAG激光器为种子光源，以后向抽运的掺镱双包层光纤为功率放大介质，经过一级光纤功率放大，获得了平均功率5.5 W，重复频率9 kHz的激光输出，脉冲宽度为575 ps，峰值功率达到1 MW。采用非临界相位匹配的LBO晶体，对该亚纳秒脉宽光纤放大器进行了单通倍频实验研究。当晶体温度为150.5 ℃、基频光功率为2.7 W时，获得了平均功率1.3 W、峰值功率250 kW的倍频绿光输出，倍频转换效率为48%。

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。

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.

实现了一种单端光纤耦合的高重复频率、窄脉冲、窄线宽及高效率的主动声光调Q全光纤脉冲光纤激光器。该光纤激光器基于光纤光栅与平面镜组合而成的线性法布里珀罗(F-P)腔结构，采用激光二极管与(2+1)×1抽运耦合器形成后向抽运，并利用单端光纤耦合声光调制器(AOM)实现了全光纤化结构的脉冲掺镱双包层光纤激光器。调Q声光开关工作在一级方向，反向输出调Q脉冲，重复频率20~100 kHz可调。在重复频率50 kHz、抽运功率5.7 W下系统获得了输出激光功率2.64 W、单脉冲能量528 μJ、脉宽56 ns、峰值功率943 W的稳定的高效率、窄线宽的窄脉冲，中心波长在1080 nm左右，线宽为0.06 nm，光光转换效率高达46%。

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。

棱镜扩束器(PBE)广泛用在准分子激光腔内光谱压窄系统中，可以有效降低光束发散角和系统内能量密度。为了实现窄线宽激光输出并降低腔内损耗，需要对棱镜扩束器的棱镜个数、单棱镜扩束倍数和棱镜顶角进行优化设计。根据棱镜扩束倍数的理论，数值分析了入射角、顶角和出射角对棱镜扩束倍数的影响，并在实验上很好地验证了扩束倍数与入射角的关系。此外，推导了激光器线宽压窄系统实现一定激光线宽输出所需的总棱镜扩束倍数。优化设计了扩束倍数M为13.3的氟化钙消色散棱镜扩束器，在此基础上，实现了0.915 pm的窄线宽ArF激光输出，实验结果与理论设计吻合。

We report a 1 018-nm ytterbium-doped double-clad fiber laser pumped by 970-nm diode. A pair of fiber Bragg gratings with reflectivities of 99.9% and 9% at a center wavelength of 1 018.9 nm are employed as cavity mirrors. The ytterbium-doped double-clad fiber is a 2.6-m-long Liekki fiber. Laser output power of 7.5 W at 1 018 nm is obtained under the pump power of 59.2 W. The overall slope efficiency of the fiber laser is about 16%. This low slope efficiency is mainly due to the incomplete absorption of the pump power.