Patent attributes
A method of coupling optical fibers containing cores or other structures that twist about the axis of one or both fibers. The fiber end faces are aligned axially to confront one another, and side view images of end regions of the fibers including the contained cores or structures are produced. For each fiber, a brightness profile of a side view image is obtained at an axially offset position from the fiber end face. One or both fibers are rotated about their axes until the brightness profiles for each fiber indicate certain cores or structures in the fibers are aligned. For each fiber, an additional amount of twist from the offset position to the fiber end face is determined. One or both fibers are rotated again to compensate for the additional twist in each fiber, so that the fibers are aligned optimally when coupled.