Functionally homogenized intensity distribution for additive manufacturing or other industrial laser processing applications

An apparatus for generating a laser output beam having a functionally homogenized, annular intensity distribution, the apparatus comprising:

• a first length of optical fiber to guide a low-moded source beam;
• a second length of optical fiber having a multi-mode confinement core configured to receive the low-moded source beam and thereby excite a population of few modes in the multi-mode confinement core such that the population exhibit an inhomogeneous intensity distribution;
• and
• a perturbation device to provide externally applied perturbation to change phase relationship without a change in a number of modes being excited in the multi-mode confinement core and vibrational perturbation of launch conditions of the low-moded source beam into the multi-mode confinement core thereby functionally homogenizing the inhomogeneous intensity distribution to generate the laser output beam having the functionally homogenized, annular intensity distribution.