能量回收型直线加速器(ERL)可能提供低发射度、高平均流强的连续电子束团, 其电子枪的光阴极需要高重复频率、高平均功率的驱动激光系统。采用先进的光纤激光技术, 特别是在激光系统中采用了掺镱光子晶体增益光纤, 能实现高重复频率高平均功率激光输出。利用啁啾脉冲放大(CPA)技术, 通过优化设计, 将重复频率100 MHz和1.3 GHz的两套激光振荡源集成到同一个激光系统, 整个激光系统的结构简化, 使用方便。两种重复频率激光倍频效率分别达到50%和30%, 绿光能达到5 W以上, 满足光阴极实验平台的使用要求。

The Energy Recovery Linac (ERL) can produce continuous electron bunches with low emittance at high average current. The photocathode electron gun needs high repetition rate, high average power drive laser system. Adopting advanced fiber laser technologies, especially using Yb-doped photonic crystal fiber in the laser system, a high repetition frequency, high average power laser system was set up. By using chirped pulse amplification (CPA) and optimizing the design, a 100 MHz oscillator and a 1.3 GHz oscillator were integrated into one laser system. The structure of the whole laser system can be simplified and easy to operate. The second harmonic generation (SHG) efficiencies of the laser system at two different repetition rates have already reached 50% and 30%, respectively. In addition, more than 5 W green light has been achieved, which meets the needs of test platform of photocathode at IHEP.