百瓦级1030nm光纤-固体混合放大激光器

Hundred-watt-level 1030 nm fiber-bulk hybrid amplified laser

光纤-固体混合放大技术能够将光纤激光器和固体放大器的优势结合,获得结构紧凑、成本低廉的高功率超短脉冲激光。因此,实验设计了基于掺镱光纤-固体混合放大技术的高平均功率超短脉冲激光器。该激光器主要由全光纤结构激光器和两级固体放大器组成,第一级为基于Yb:YAG单晶光纤的固体放大器,第二级为基于无侧面抛光的棒状Yb:YAG晶体的主放大器。超短脉冲全光纤前端平均输出功率为6.5 W,重复频率52.9 MHz,脉冲宽度47.5 ps。第一级单晶光纤放大器采用单通放大形式,在反向泵浦功率182 W时获得40 W的平均功率。第二级固体放大器同样为单通放大,在反向泵浦功率307 W时获得平均功率122.9 W的超短脉冲激光输出,滤除热退偏激光后获得了107.3 W的线偏振超短脉冲激光,对应斜效率为26.1%。此时测得脉冲宽度为12.1 ps,中心波长为1 030.6 nm,光谱宽度为2.4 nm。在最大输出功率107.3 W时,测得水平和垂直方向的光束质量因子M_(x)^(2)=1.45,M_(y)^(2)=1.20。

Fiber-bulk hybrid amplification technology combines the advantages of fiber lasers and bulk amplifiers to obtain a compact and low-cost high power ultrashort pulse laser. Therefore, a high average power ultrashort pulse laser was designed based on Yb-doped fiber-bulk hybrid amplification technology. The laser was consisted of an Yb-doped all-fiber laser and two-stage bulk amplifiers. The first bulk amplifier was based on Yb:YAG single crystal fiber, and the second bulk amplifier was based on Yb: YAG rod with unpolished barrel. The all-fiber front end delivered 6.5 W average power, 52.9 MHz repetition rate and 47.5 ps pulse duration. The single crystal fiber amplifier obtained an average power of 40 W at the backward pump power of 182 W through a single-pass amplification. The Yb: YAG rod amplifier outputted an average output power of 122.9 W at the backward pump power of 307 W in single-pass configuration. After removing the depolarization part introduced by thermal effect, an average output power of 107.3 W with linear polarization state was obtained, and the corresponding slope efficiency was 26.1%. The pulse width of 12.1 ps and center wavelength of 1030.6 nm with spectral width of 2.4 nm were achieved. At the maximum output power of 107.3 W, a beam quality factor of 1.45and 1.20 were measured along the vertical and horizontal direction, respectively.