56-W Frequency-Doubled Source at 530 nm Pumped by a Single-Mode, Single-Polarization, Picosecond, Yb $^{3+}$ -Doped Fiber MOPA

We report a frequency-doubled green source at 530 nm pumped based on an all-fiber, picosecond, single-polarization Yb ³⁺-doped fiber master oscillator power amplifier (MOPA) delivering 20-ps pulses at user selectable repetition rates of up to 910 MHz and an average output power in excess of 100 W at 1.06 ??m. The output of the MOPA was frequency-doubled using a lithium triborate crystal. Up to 56 W of green light was generated at a corresponding repetition rate of 227 MHz at an overall conversion efficiency of 56%. The diode-to-green optical power conversion efficiency was 37%.