报道了一个三级主振荡功率放大(MOPA)结构的瓦级皮秒光纤激光器。第一级利用半导体可饱和吸收镜(SESAM)和光纤光栅组成线性腔,构建了一个低功率的被动锁模掺Yb3+光纤激光器,其最大平均输出功率为9.2 mW,作为整个激光器的种子源;第二级采用单模掺镱光纤放大器对种子光进行预放大,得到108 mW平均输出功率;第三级采用带树状耦合器的双包层掺镱光纤放大器进行功率放大,获得了1.9 W平均输出功率。得到的脉冲脉宽36 ps,中心波长1064 nm,重复频率29.6 MHz,峰值功率1.8 kW,相应的单脉冲能量为61 nJ。实验中观察到种子源输出光谱中有一个凹陷,这是由于光纤光栅反射率过高并且带宽较窄引起的。

A watt-level Yb-doped ps fiber laser in tri-stage master oscillator power amplifier (MOPA) configuration is investigated. The first stage is a semiconduttor saturable absorption mirror (SESAM) passively mode locked fiber laser with a low average output power of 9.2 mW. A fiber Bragg grating (FBG) is utilized as the output laser cavity mirror. The second stage is an Yb-doped single mode fiber amplifier with a moderate average output power of 108 mW. The last stage is a double clad Yb-doped power amplifier which increases the average output power to 1.9 W. The center wavelength of the mode locked pulse is 1064 nm with a pulse width of 36 ps. The pulse repetition rate,the peak power and the energy of a single pulse is 29.6 MHz,1.8 kW and 61 nJ,respectively. A small dip located at the center laser wavelength is observed on the output spectrum,which is considered to be caused by the high reflectivity and the narrow bandwidth of the FBG.