Coherent Superposition of Pulsed High-Brightness Tapered Amplifiers

Coherent beam combining (CBC) of high brightness tapered amplifiers (TPAs) is a promising approach for the development of high power semiconductor laser sources with excellent beam quality and offers a pathway to future direct diode high brightness system. Operation of the amplifiers in quasi continuous wave (QCW) mode allows to overcome the thermal limitations in the amplifiers and to test their full power scaling potential. Additionally, high brightness QCW sources with high spectral purity are in demand as NIR pump sources for nonlinear frequency conversion to address medical applications of modulated high power visible laser sources. In this paper we discuss dynamic effects in pulsed high brightness tapered amplifiers and demonstrate their coherent superposition for brightness scaling. We use state-of the art TPAs with the so called ELOD2 epitaxial design, which allows us to maintain close-to-diffraction limited beam quality at high powers.