Laser-scattering-based method for investigation of ultra-low-loss arc fusion-spliced single-mode optical fibers

Standard arc fusion splicing of optical fibers does not include buckling, angular, or lateral offsets. With fusion splicing, a tiny core axial offset exists. It originates from an index modification in the core region due to the heat treatments accompaniment to the splice process. Such axial offset practically contributes to causing the major power loss. In this paper, a new method based on the forward-scattering technique is described to examine standard exactitude ultra-low-loss fusion splicing of single-mode fibers. The method provides the ability to estimate the splice loss. For the first time, a modified scattering pattern is recorded for the spliced intermediate junction of arc fusion-spliced fibers. The deformed scattering pattern takes a diffractionlike shape pattern. The fringe separation between the most two outer solid fringes showed a direct proportionality to the power loss due to splicing. The method could be used to suppress such inescapable axial offset significantly, even in fibers with a large core eccentricity. An ultra-low-loss splicing without conventional power monitoring could be achieved.