高重频风冷声光调 Q光纤激光器实验研究

摘要

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.%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％。