High-power laser system for forming laser irradiation zone with specified dimensions and power density distribution for thermal surface treatment applications

A laser system for forming a zone with a predetermined shape and desired power density distribution (PDD) on the surface to be thermally treated, comprising:

• a plurality of laser sources operable to controllably output respective source beams with respective non-controlled PDD;
• a plurality of fiber trains guiding respective source beams along a path;
• at least one laser head receiving downstream fiber ends of respective fiber trains;
• an optical mixer mounted in the laser head and positioned opposite the fiber ends so as to receive, guide and combine the source beams into a system output beam, wherein
• the optical mixer is configured to shape the system output beam so that it forms a beam spot defining the predetermined shape of the zone, and
• the output fiber ends defining a spatial arrangement providing the desired PDD across the beam spot of the system output beam and within the surface zone.