Patent ID: 7080529

Claim:
A method for making a multicore optical waveguide having a cross-section of at least about 0.3 millimeters, two or more inner cores, and a cladding surrounding the two or more inner cores, comprising the steps of: assembling a preform for drawing the multicore optical waveguide by providing an outer tube having a cross-section of at least about 0.3 millimeters, arranging two or more preform elements in relation to the outer tube, and arranging a hollow inner tube inside the outer tube, wherein the two or more preform elements supply the two or more inner cores; notching the inner tube with two or more notches providing a respective one of the preform elements in each notch; heating the preform; and drawing the optical waveguide from the preform, thereby defining the cross section that is greater than about 0.3 millimeters in all directions upon completion of the drawing, and thereby leaving in an area of the optical waveguide that has been drawn a longitudinal aperture extending through the optical waveguide, wherein the longitudinal aperture is formed by the hollow inner tube.