High-Power Yb-Doped and All Fiber-Based Nanosecond MOPA Laser

We report the results obtained by using a newly designed 300-μm-core-diameter Yb-doped fiber with a large cladding absorption of 23 dB/m at 976 nm. An average power of 512 W, a maximum pulse energy of 51.2 mJ laser is realized using the 300-μm-core Yb-doped fiber in the main amplifier with a slope efficiency of 72%. The entire laser system adopts an all-fiber construction with pulse control system. These results extend average power and peak power of nanosecond all fiber-based laser, exceeding to the 500 W and 1 MW regime simultaneously for the first time to the best of our knowledge.