Remapping diffractive beam shaping of a fiber laser for focused tophat profiles

Diffractive beam shaping, using a remapping approach, requires a laser source that is well characterized and stable. Recent advances in the development of fiber lasers have shown stable, high quality, TEM00 single mode performance at powers < 200 Watts for 1090 nm. This paper will give a detailed account of the design and experimental results for a 5.5 mm 1/e2 fiber lasers shaped by an off-axis diffractive beam shaper to produce tophat focused spots < 50 microns. One application of interest is in the area of micro welding of thin stainless steel sheets. Experimental data will be presented for this micro welding application.