Fusion splicing of multi-layer optical fiber bundles

Abstract

First and second optical fiber groups, each composed of optical fibers in layers, are held by alignment mating means, with the optical fibers placed at predetermined positions and end faces of corresponding pairs of them butted with each other. A light beam emitted from a CO.sub.2 laser is focused by a focusing optical system on the joints of the butted optical fibers. When the light beam is focused on one pair of butted optical fibers to fusion-splice them, the diameter of the focused light beam reaching the optical fibers adjacent to the irradiated ones is large so that their heating temperature by the focused light beam may not exceed their melting point. The focusing optical system and the alignment mating means are moved relative to each other to fusion-splice the butted optical fibers in succession.