We report on a spectral combination of four $2\mathrm{ns}$ pulsed fiber amplifier systems to a total output power of $187\mathrm{W}$ at a $50\mathrm{kHz}$ repetition rate resulting in $>3.7\mathrm{mJ}$ of pulse energy and $1.7\mathrm{MW}$ of pulse peak power. A dielectric reflection grating is used to merge the four individual beams to one output with close to diffraction-limited beam quality independent of the power level. The output characteristics are beyond the capabilities of a single emitter and further scaling in a straightforward way appears to be feasible.