Patent ID: 11960120
Assignee: FUJIKURA LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method for aligning multicore fibers each having three or more cores disposed on a circumference centered on a central axis of a clad, each of the cores being disposed the same in each of a pair of the multicore fibers, the method comprising:
a first imaging step of capturing a first set of images of side surfaces of each of the pair of multicore fibers before and after rotating each of the pair of multicore fibers by P° a number of times (N) rounded up such that N=360/P is an integer, wherein
in each of the multicore fibers, a plurality of corners are defined by adjacent line segments that connect a center of the clad to each of the cores, the plurality of corners including:
a first corner with a size of P° and two or more consecutive positions in a circumferential direction, and
a second corner with a size different from P°, and

for each of the N times, each of the pair of multicore fibers is rotated about the central axis in a state where end surfaces of the pair of multicore fibers face each other and the central axis of each of the pair of multicore fibers coincide with each other;

a first calculation determining step of determining, for each of the pair of multicore fibers, a similarity between an image from the first set of images captured before a rotation by P° and an image from the first set of images captured after the rotation by P° for each of the N times the each of the multicore fibers is rotated by P°;
a first rotation position determining step of determining specific relative rotation positions of the pair of multicore fibers in which a cross-correlation between a plurality of columns of similarities of one multicore fiber and a plurality of columns of similarities of an other multicore fiber becomes highest; and
a first rotation step of rotating at least one of the pair of multicore fibers about the central axis such that the cross-correlation between the one multicore fiber and the other multicore fiber has a relationship of the specific relative rotation positions.