报道了基于主振荡功率放大(MOPA) 工作方式的吉赫兹级窄线宽、高峰值功率光纤激光器。该激光器以脉冲调制的分布反馈式单频半导体激光器为种子源，波长为1064.12 nm，脉冲宽度为3.92 ns，重复频率在10~50 kHz内连续可调。采用光纤双程放大结构的预放大级以增加小信号放大能力并抑制强抽运下的自发放大辐射，优化功率放大级光纤长度以抑制窄线宽激光放大过程中的受激布里渊散射，在重复频率为10 kHz时，获得光谱线宽为1.5 GHz、峰值功率达15 kW的脉冲激光输出。实验研究了不同重复频率时的输出激光脉冲特性。

A GHz narrow-linewidth high-peak power nanosecond fiber laser based on the master oscillator power amplifier (MOPA) is reported. The modulated distributed feedback single-frequency diode laser seed delivers pulses with wavelength of 1064.12 nm, pulse width of 3.92 ns, and tunable repetition rate from 10 kHz to 50 kHz. A double-pass structure is used in the preamplifier to boost small signal and suppress amplification of spontaneous emission under intense pump. In the power amplifier the stimulated Brillouin scattering is avoided by shortening fiber length. Pulsed laser with 1.5 GHz linewidth and 15 kW peak power is obtained at a repetition rate of 10 kHz. The output pulse characteristics at different repetition rates are studied.