Beam intensity profile tailoring with a composite, tapered optical fibre

A composite, optical fibre comprising of:

• at least one primary waveguide,
• at least one secondary waveguide, and
• the at least one secondary waveguide surrounds or is within the primary waveguide,
• wherein the composite optical fibre has a uniformly increasing diameter from one end to another such that the at least one primary waveguide and the at least one secondary waveguide each have a uniformly increasing diameter from one end of the composite optical fibre to another end of the composite optical fibre.

A method of modifying a beam intensity profile of a laser beam by the steps of:

• providing at least one secondary waveguide within or surrounded by at least one primary waveguide;
• and
• tapering both the primary waveguide and the secondary waveguide together such that a laser beam mode is caused to be transferred from one waveguide to the other along the tapered section;
• whereby a beam intensity profile of an input laser beam is modified.