255 W picosecond MOPA laser based on self made Yb doped very large mode area pho

We report on the amplification of high-average-power and high-efficiency picosecond pulses in a self-made very-large-mode-area Yb-doped photonic crystal fiber (PCF). The PCF with a core diameter of 105 μm and a core numerical aperture of 0.05 is prepared by the sol-gel method combined with the powde