Fig. 1. (a) Upper laser level population density and (b) energy storage as functions of time under different pump power.不同抽运功率下(a)激光上能级粒子数密度, (b)有源光纤储能随时间t的变化关系

Fig. 2. Energy storage with 5 W launched pump power and (a) normalized energy density with different extraction efficiency as a function of time (PRR = 10 kHz), (b) the relationship between output pulse intensity and seed PRR.抽运功率5 W时有源纤储能及(a)不同提取效率下归一化储能密度随时间的变化(PRR = 10 kHz), (b)放大级输出脉冲强度与种子光重复频率之间的关系

Fig. 3. Output pulse energy as a function of PPR (3 W launched pump power).输出脉冲能量与种子光重复频率关系曲线(抽运功率3 W)

Fig. 4. Experimental setup of the Ytterbium-doped amplifier in the upper-laser-level lifetime measurement.基于掺镱光纤激光放大器的激光上能级寿命测量实验装置

Fig. 5. (a) Optical spectra and (b) pulse waveform of the seed pulse and pre-amplifier output (seed PRR of 1 kHz and pulse duration of 2.25 μs).种子光PRR为1 kHz、脉宽为2.25 μs时　(a)预放大前后光谱, (b)预放大前后脉冲形状

Fig. 6. Upper-laser-level lifetime measurement result of (a) LMA-YDF-12/125, (b)SM-YDF-5/130, (c) PLMA-YDF-10/125-M and (d) YDF-6/125 fibers.激光上能级寿命测量结果　(a) LMA-YDF-12/125光纤; (b) SM-YDF-5/130光纤; (c) PLMA-YDF-10/125-M光纤; (d) YDF-6/125光纤

Fig. 7. Test results of PLMA-YDF-10/125-M at 11 μJ, 16 μJ and 25 μJ seed pulse energy.种子光脉冲能量为11, 16, 25 μJ时对PLMA-YDF-10/125-M光纤的测量结果