Optical fiber article for handling higher power and method of fabricating or using

A method for making an optical fiber having a first core and a second core spaced from the first core, the method comprising:

• (a) providing an optical fiber preform extending in a longitudinal direction, the optical fiber preform comprising:
• a first core;
• a second core spaced from the first core;
• and
• first and second regions, said first region when viewed in cross section having an outer perimeter having a first substantially straight length and the second region having an outer perimeter having a second substantially straight length facing said first substantially straight length, the first straight length and the second straight length being contiguous and substantially parallel;
• one of said first and second regions comprising said first core and a cladding disposed about said first core and the other of said first and second regions comprising said second core and a cladding disposed about said second core;
• said optical fiber preform being constructed and arranged such that the optical fiber preform can be drawn;
• and
• (b) drawing the optical fiber from the optical fiber preform while rotating the optical fiber preform about an axis passing through the first core to provide the optical fiber,
• wherein the optical fiber is configured such that the first core of the optical fiber is multimode at a selected wavelength of operation and the second core of the optical fiber is spaced apart from and winds around the first core of the optical fiber and has a selected longitudinal pitch,
• wherein at said wavelength of operation the second core of the optical fiber couples to a higher order mode of the first core of the optical fiber and increases the attenuation thereof relative to the fundamental mode of the first core of the optical fiber, and
• wherein the term “cross section” means cross section taken perpendicular to the longitudinal direction.