200W average power 1mJ pulse energy from spectrally combined pulsed sub-5 ns fiber laser source

In this contribution, we report on spectral combination of four sub-5ns pulsed fiber amplifier systems with an average output power of 200W at 200kHz repetition rate resulting in 1mJ of pulse energy. A dielectric reflection grating is used to combine four individual beams to one output possessing a measured M 2 value of 1.3 and 1.8, respectively, independent of power level. Extraction of higher pulse energies and peak powers will be discussed.