15 mJ and high-peak-power nanosecond pulse based on all-fiber MOPA system

We present the comprehensive elucidation of an exclusively fiber-based nanosecond Master Oscillator Power Amplifier (MOPA) laser system, integrating a 100-μm-core ytterbium-doped fiber within the primary amplification stage and a 300- μm-core Quartz Block Head (QBH) delivery configuration. The laser system hinges upon a diode laser seed, yielding a pulse train with pulse duration of 50 ns and repetition rate of 30 kHz. Consequently, the resultant pulse profile exhibits a final full width at half-maximum (FWHM) of 8.8 ns, concomitantly achieving a pinnacle power output exceeding 1.5 MW. The average power output attains a magnitude of 456 W, concomitant with a maximal pulse energy of 15.2 mJ. These findings collectively underscore a noteworthy advancement in both average and peak power outputs, notably within the context of narrow pulse durations and low repetition rate regimes.