为了研究如何从脉冲种子光经放大器后获得能量为毫焦级、纳秒级脉宽的激光脉冲,以及重频、受激喇曼效应对输出激光脉冲的影响,采用基于主振荡动率放大方式建立了3级脉冲双包层掺Yb光纤放大器的瞬态理论模型。在不同重频下对能量为10nJ、脉宽为100ns的脉冲种子光经放大后的脉冲能量、峰值功率、平均功率、脉宽及受激喇曼效应进行了数值模拟。计算数据表明,当重频小于200Hz时输出激光脉冲的能量、波形受重频的影响很小,可以忽略不计,在适当参量下受激喇曼效应对各级放大输出几乎没有影响。结果表明,适当选择3级光纤放大器的各项参量可以实现毫焦级的激光脉冲输出。

In order to obtain certain laser pulse with millijoule(mJ) order energy and nanosecond(ns) order pulse width after amplifying the pulsed seed laser,and to find the impact of repetition rate and simulated Raman scattering on laser pulse output,the dynamic model of a three-class ytterbium-doped double-clad fiber pulsed amplifier was established on the base of master oscillator power amplifier.Then the pulse energy,peak power,average power,pulse width and stimulated Raman scattering effect,arose from an amplifier of the pulsed seed laser with 10nJ energy and 100ns pulse width at different pulse repetition frequency,were simulated.The simulation results show that output laser energy and waveform are so slightly affected by the frequency that its effect can be ignored when the pulse repetition frequency is less than 200Hz,and that the Raman effect almost has little impact on the output property of each class amplifier if suitable parameters are selected.According to the numerical analysis,mJ order energy can be obtained from a three-class fiber amplifier with suitable parameters.