脉冲光纤激光器具有输出光束质量好、峰值功率高等优势，易于激发晶体内部的非线性效应。晶体非线性效应能够将光纤激光的近红外输出波段变换至深紫外或中红外等波段。利用实验室自主搭建的中心波长为1064 nm，脉宽为650 ps的脉冲光纤激光器抽运KTP(磷酸钛氧钾)晶体，实现了高功率超短脉冲对1064 nm激光的单程倍频，输出532 nm激光。将脉冲宽度由650 ps压缩至1 ps后，抽运激光的峰值功率密度达到24.97 GW/cm2，有效地将单程倍频转换效率从0.8%提高到8.4%。研究了不同平均功率、脉宽、光斑直径的超短脉冲下KTP晶体的倍频效率，验证了未来在振荡腔结构下实现KTP晶体高效倍频的可行性。

With high peak power and good beam quality, it is easy for pulsed fiber lasers to trigger nonlinear process in a nonlinear crystal, and the near-infrared laser can be transferred into the ultra-violet or mid-infrared regime. In an experiment, the homemade high power pulsed fiber laser with central wavelength of 1064 nm and pulse duration of 650 ps is used to pump KTP (potassium titanyl phosphate) crystal, and the 532 nm laser is output after second-harmonic generation (SHG). In the process, the pulse width is compressed from 650 ps to 1 ps, the peak power density of the pump laser is raised to 24.97 GW/cm2, and the SHG efficiency increases from 0.8% to 8.4%. SHG efficiency is investigated for the pump laser of different average power, pulse width and beam spot, and the possibility to achieve highly efficient SHG with an oscillator is proved.