为了探讨多级级联掺镱光纤放大器的脉冲放大特性,采用主振功率放大技术(MOPA),实验研究了3级级联、全光纤结构的高增益脉冲激光放大器。通过优化各放大级增益光纤的长度和抽运光功率的大小,在保证高放大增益的同时,抑制了掺镱光纤中自发辐射光的自生激光振荡,并对第2放大级进行了结构优化。在脉冲激光放大过程中实现了中心波长1064nm、脉冲宽度19ns、重复频率5kHz、峰值功率3.8kW、总放大增益达43.8dB的稳定激光输出。同时,制作完成了1台结构紧凑、全光纤结构的脉冲光纤放大器样机,对重复频率1Hz的低频脉冲信号进行了放大实验,也得到了43.2dB的输出信号增益。结果表明,本脉冲光纤放大器对低频脉冲信号有很好的放大效果。

In order to study the characteristics of pulse amplification in multi-stage cascade ytterbium-doped fiber amplifiers,the three-stage high-gain pulse fiber amplifier with all-fiber structure was experimentally studied based on the master oscillator power amplifier(MOPA) technology.The length of the gain fibers and the pump powers in every stage were optimized experimentally to obtain high signal gain,and the spurious lasing of the amplification stimulation emission light was suppressed at the same time.The stable output was obtained with a peak wavelength of 1064nm,pulse duration of 19ns,repetition frequency of 5kHz,the peak power of 3.8kW,and the total gain of 43.8dB.The compact prototype of an all-fiber pulse fiber amplifier was developed and used to amplify a pulse signal at 1Hz repetition frequency,a signal gain of 43.2dB was obtained.The results show that this amplifier has a good amplification effect on the pulse signal at a low repetition frequency.