High repetition rate, high average power nanosecond laser using two Yb-doped PCF rod fibers

We have developed a high-peak and high-average power Yb-doped fiber laser system based on polarization-maintained 100-μm PCF-rod fiber. A maximum average output power per beam of over 360 W (pulse width: 14ns, pulse energy: 1.31 mJ, repetition rate: 300 kHz) is obtained with a slope efficiency of 64 %. We obtained the output power 640 W of two beams at a time.