Coherent beam combining of tapered amplifiers under QCW regime

We demonstrate the coherent beam combining of four high-brightness tapered amplifiers in quasi continuous wave operation. A maximum combined power of 22.7 W was achieved with > 64 % combining efficiency. The beam quality of the combined output was increased with regard to the individual amplifiers thanks to the inherent clean-up of the superposition, resulting in a diffraction-limited power \gt 20 W.