结合Er/Yb共掺双包层光纤(EYDCF)和主振荡功率放大(MOPA)技术,采用高功率多模抽运方式设计和实验研究了全光纤化两级放大器。分析了放大器的各种性能参数; 1550 nm连续光放大得到最大斜率效率为29%,最大输出功率1.52 W, 功率稳定度0.4％;2 kHz脉冲放大时得到最大输出功率1.1 W,功率稳定度0.45％, 最大斜率效率25%。并从放大后光谱和时域波形分析了导致脉冲放大时斜率效率和功率转换效率较低的主要原因为Yb3+离子波段放大自发辐射(ASE)的出现和Er离子波段ASE的过多积累。在高功率放大时, 增益随输入信号功率增大迅速下降; 同时结合抽运光频谱随驱动电流变化分析了其对放大器性能的影响。

Using the high power multimode pumping method, the Er/Yb co-doped double clad fiber (EYDCF) two-stage master oscillation power amplification (MOPA) based on all-fiber configuration is experimentally studied. With continuous wave (CW) amplification, the maximal output power is 1.52 W, the degree of stability is 0.4% and the slope efficiency is 29%. While with 2 kHz pulsed amplification, the maximal output power is 1.1 W, the degree of stability is 0.45% and the slope efficiency is 25%. The fact that the slope efficiency and the power conversion efficiency (PCE) of pulsed amplification are lower than the CW is caused by the appearance of the Yb3+ band, and the accumulation of the Er3+ band ASE deduces from the output spectrum and time domain waveform. The gain of the amplifier decreases seriously as the input power increases under the high power amplification condition. The impact that the fluctuation of the pump spectrum with the driven current on the amplifier performance is also analyzed.