10 kW-level spectral beam combination of two high power broad-linewidth fiber lasers by means of edge filters

Abstract

We demonstrated a scheme to spectrally combine two high power, broad-linewidth single beams using a steep edge filter as the combining element. 10.12 kW combined output power is achieved with a beam quality of M2 x = 11.4 and M2 y = 10.4. To the best of our knowledge, this is the highest output power ever reported for the filter based SBC system. Despite the broad emission spectrum of the single channel, the combining efficiency is measured to be 98.9%, which proves the high efficiency of the filter for both the reflection and transmission cases. A detail analysis of the thermal behavior is carried out to aid in the optimization of the beam quality. This SBC system permits the efficient combining of the beams with broad linewidth and provides another approach to achieve a combined output beam beyond 10 kW level.