Core-axis-alignment method to achieve ultra-low-loss fusion splicing for single-mode optical fibers.

A new axis-alignment method for ultra-low-loss splicing of single-mode optical fibers is described. An estimation is made of the fiber axis movement resulting from surface tension between fiber end faces in arc-fusion splicing. By assigning an equivalent amount of core-axis offset to the estimated axis movement, it is possible to achieve much lower loss in fusion splicing than by conventional axis alignment with power monitoring, even when the core eccentricity is large.