采用四级主振荡功率放大（MOPA）结构，研制了高功率全光纤掺镱皮秒光纤激光器。种子源采用基于非线性偏振旋转（NPR）效应的被动锁模光纤激光器，中心波长为1062.8 nm，重复频率为17.51 MHz，谱线宽度为5 nm，平均功率为7.14 mW。为了抑制功率放大过程中的非线性效应，通过全光纤重复频率扩展器将种子脉冲激光的重复频率提高到281.7 MHz。主功率放大级以长度为4.8 m的大模场面积掺镱双包层光纤作为增益介质。在抽运功率为60 W时，获得的最大平均输出功率为31.2 W，光光转换效率为52%。输出激光脉冲的中心波长为1063.7 nm，脉冲宽度为10.2 ps，重复频率为281.7 MHz，谱线宽度为7 nm，并对激光脉冲的时域和频域特性进行了分析。

A high-power all-fiber Yb-doped picosecond fiber laser is achieved via a four-stage master oscillator power amplifier (MOPA) configuration. The seed source is a passively mode-locked fiber laser based on nonlinear polarization rotation (NPR) effect, with a central wavelength of 1062.8 nm, a repetition rate of 17.51 MHz, a spectral linewidth of 5 nm and an average power of 7.14 mW. To suppress the nonlinear effects in the process of power scaling, the repetition rate is upgrade to about 281.7 MHz through an all-fiber repetition rate extender. A 4.8 m large mode area (LMA) Yb-doped double clad fiber is utilized as gain medium in the main power amplifier. The maximal average output power of 31.2 W is obtained at the pump power of 60 W, corresponding to an optical-to-optical conversion efficiency of 52%. The output laser pulse has a central wavelength of 1063.7 nm, a pulse duration of 10.2 ps, a repetition rate of 281.7 MHz and a spectral linewidth of 7 nm. Moreover, the characteristics of the laser pulse are analyzed both in time and frequency domain.