为了实现功率稳定的风冷高重频脉冲光纤激光器, 采用主振荡功率放大结构, 对声光调Q的全光纤激光器进行了研究。振荡级采用声光调Q方案, 以光纤光栅对为激光器腔镜, 915nm激光二极管连续抽运, 得到了中心波长1064nm、重复频率10kHz到130kHz可调的激光脉冲输出。采用两级大模场双包层光纤放大, 实现了平均功率101W、脉冲宽度328.1ns、3dB光谱宽度0.6nm的激光输出。第二放大级光光转换效率69%, 激光器总光光转换效率达62.7%。分析了声光调Q产生的宽种子光脉冲经放大后发生波形畸变的原因。结果表明, 采用915nm抽运波长提高了激光器输出激光功率稳定性, 在风冷的情况下输出功率长期稳定性优于2%。

In order to obtain the air cooling high repetition fiber laser with stable power, an acoustic-optical Q-switched all-fiber laser with master oscillator power amplifier structure was studied. The oscillator used the scheme of acousto-optic Q-switched with a pair of fiber Bragg grating as laser cavity mirrors. Pumped by 915nm laser diodes, 1064nm laser pulse output was acquired with adjustable repetition rates from 10kHz to 130kHz. Through two-stage double clad large mode area fiber amplifier, 101W output power was obtained with 328.1ns pulse width. The 3dB optical spectrum width of fiber laser was 0.6nm. Optical-optical efficiency of the second amplifier stage was 69%. The total optical-optical efficiency of laser was 62.7%. The distortion cause of long width seed pulse created by acousto-optic Q-switched through the amplification was studied. The experimental results show that pumped by 915nm laser diodes, the long-term stability of output power is proved to less than 2% under air cooling.