Low fill factor diode laser bars with high brilliance from 808 nm to 1020 nm for fibre coupling

In recent years high brilliance semiconductor diode lasers are gaining attraction for the industrial laser market. The emerging generation of multi kilowatt fibre lasers require brilliant pump sources and additionally fibre coupled direct diode lasers increasingly compete with solid state lasers in many industrial areas. This paper investigates diode lasers, which combine several advantages from single emitters and high fill factor laser bars when considering fibre coupling applications. New facet technologies enable the laser to be driven at higher powers per emitter allowing a reduction in fill factor without penalty in total output power per laser bar. These low fill factor bars enable reliable and efficient operation at output power densities comparable to single emitters. The resulting beam parameters allow coupling into a single fibre with low effort in beam shaping or fibre combining.