Patent ID: 7592568
Filing Date: 2009-09-22
Classification: B23K,H01S

Abstract:
1. Apparatus for the industrial processing of a material comprising a fibre laser, wherein the fibre laser is configured to emit optical radiation, the apparatus configured such that the optical radiation can form an optical power distribution on a surface of the material, the optical power distribution including first and second optical powers which are located at respective first and second radii from a centre of the optical power distribution and which are of substantially higher intensity than a third optical power which is located at a third radius from the centre of the optical power distribution and which is smaller than the first and the second radii, and wherein: the fibre laser comprises a waveguide having an output end, wherein the waveguide is a single mode waveguide having a refractive index profile configured to provide an optical power distribution at the output end comprising a substantially ring mode power distribution; the apparatus includes focusing optics configured to direct the optical radiation onto the material; the waveguide is defined by a guidance profile across its cross section, the guidance profile being defined by the refractive index profile and an optical gain profile; the guidance profile and the focusing optics are configured to produce the optical power distribution on the surface of the material; and the optical power distribution at the output end of the waveguide is related to the optical power distribution at the surface of the material by an inverse transform of the focusing optics, and further wherein the guidance profile of the waveguide is an inversion of the optical power distribution at the output end of the waveguide.