光纤技术为惯性约束聚变激光驱动器前端系统提供了许多便利, 如便于分路、鲁棒性和稳定性。提出了一套全光纤前端的方案来适应未来高能拍瓦激光装置对种子源的需求。实验研究了这套用于产生高能短脉冲激光的光纤前端系统的啁啾脉冲展宽与放大特性。采用锁模振荡器的相位锁定信号作为系统的参考时钟, 将各级光开关器件进行同步。系统采用波导幅度调制器来选取需要的信号重复频率, 并用声光调制器(AOM)对放大器级间放大自发辐射(ASE)光进行抑制。通过大模场光纤放大器后系统输出啁啾脉冲峰值功率4.1 kW, 脉宽760 ps, 输出脉冲稳定。鲁棒性、高可靠性和使用便捷的优点使这套前端系统为高能拍瓦激光装置提供了一种可选择的种子脉冲产生方式。

The fiber technology provides many advantages for the front end of a laser driver, such as convenience to divide, robustness and stability. A fiber front end scheme is proposed to meet the requirements of next generation high-power petawatt laser facility. Experimental investigation has been done to focus on the broadening and amplification of the chirped pulse. Phase-locked signal of the mode-locked fiber laser is set as the reference clock for the system to synchronize the optical switches. Waveguide amplitude modulator is used to choose the needed frequency of signal. Acoustic optical modulators (AOM) are used to restrain the amplified spontaneous emission (ASE) between fiber amplifiers. Experimental results show that after passing through the large-mode-area ytterbium amplifier, chirped pulse with 4.1-kW peak power, 760-ps is obtained. High degree of robustness, reliability and ease of use make this fiber front end an optional seed pulse for high-power short pulse laser facilities.