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本文报道了一种主振荡光纤放大系统（MOFA），围绕提高峰值功率和增大系统重复频率调制范围两方面进行了实验研究。实验采用电脉冲和声光调制的方式对光脉冲序列进行调制，抑制了半导体种子源在小信号放大时产生的放大自发辐射效应（ASE）和自激振荡，摆脱了种子源对系统重复频率的限制，使系统在 1 k Hz ~ 200 k Hz 范围内连续可调。而且，在声光调制器对光脉冲调制过程中，声光 Q 开关有效减小了放大过程中由于自相位调制引起的光谱展宽。另外，为了进一步提高光纤激光系统的峰值功率和输出光束质量，实验采用大模场棒状光子晶体光纤作为增益介质，有效提高了模场面积、降低了纤芯数值孔径， 抑制了因峰值功率过高引起的非线性效应，提高了光脉冲的峰值功率和输出光束质量，最终实现了脉冲宽度为 1.12 ns、峰值功率达到 2.01 MW 的稳定光脉冲输出， =1.49， =1.54。
In this paper, a main oscillator optical fiber amplification system (MOFA) is reported, and experimental studies are carried out around the two aspects of increasing the peak power and increasing the modulation range of the system repetition frequency. Experiments using electrical pulse and acousto-optic modulation of the optical pulse sequence modulation, inhibit the semiconductor seed source in the small signal amplification amplified spontaneous emission effect (ASE) and self-excited oscillation, get rid of the seed source on the system repetition rate Limit to make the system continuously adjustable from 1 kHz to 200 k Hz. Moreover, during the optical pulse modulation of the acousto-optic modulator, the acousto-optic Q switch effectively reduces the spectral broadening due to the self-phase modulation during amplification. In addition, in order to further improve the peak power and the output beam quality of the fiber laser system, large mode field rod-like photonic crystal fiber is used as the gain medium to effectively increase the mode field area, reduce the core numerical aperture, The non-linear effect was improved. The peak power of optical pulse and the quality of output beam were increased. Finally, a stable optical pulse with a pulse width of 1.12 ns and a peak power of 2.01 MW was obtained, = 1.49, = 1.54.