通过数值模拟和实验研究了一种基于大模场面积光子晶体光纤的高功率全正色散自相似锁模激光器。激光器采用长为1.9 m的掺镱双包层大模场面积光子晶体光纤作为增益介质,腔内没有引入色散图,整个激光器工作在全正色散域。激光器采用环形腔结构,利用非线性偏振旋转锁模和一个窄带高斯滤波器实现了稳定的自相似锁模运转。实验最终获得了直接输出平均功率为5 W,重复频率为72 MHz,单脉冲能量超过69 n J,脉冲宽度为1.699 ps的自相似锁模脉冲输出,经过腔外1200 line/mm的透射光栅对压缩后脉宽为84 fs。激光器可以实现自启动锁模,光束质量因子M2为1.41。 A high-power full-positive dispersion self-similar mode-locked laser based on large-mode-area photonic crystal fiber is studied by numerical simulation and experiments. The laser uses a 1.9 m long ytterbium-doped double-clad large-mode-area photonic crystal fiber as the gain medium. The dispersion diagram is not introduced into the cavity. The entire laser works in the all-positive dispersion domain. The laser adopts a ring cavity structure, and uses a non-linear polarization rotation mode locking and a narrow-band Gaussian filter to achieve a stable self-similarity mode locking operation. Finally, we obtained a direct output self-analog mode-locked pulse output with an average power of 5 W, a repetition frequency of 72 MHz, a single pulse energy of more than 69 n J and a pulse width of 1.699 ps. The compressed pulse width is 84 fs. The laser can be self-starting mode-locked, beam quality factor M2 is 1.41.