US Patent 10281656 Electively coupling a laser beam into a multi-clad fiber

The invention concerns a method for generating a laser beam (3) with different beam profile characteristics, whereby a laser beam (2) is coupled into one fiber end (1a) of a multi-clad fiber (1), in particular a double-clad fiber, and emitted from the other fiber end (1b) of the multi-clad fiber (1) and whereby, to generate different beam profile characteristics of the output laser beam (3), the input laser beam (2) is electively coupled either at least into the inner fiber core (4) of the multi-clad fiber (1) or at least into at least one outer ring core (6) of the multi-clad fiber (1), as well as a corresponding arrangement (10).