Optical coupler having a tapered fused region

摘要

An optical coupler having a tapered fused region produced by locally heating the periphery of a plurality of aligned optical fibers, each having a core and a cladding, so that the optical fibers fuse together at the heated part, and then drawing the resulting fused region by pulling. The length of the fused region is not longer than 10 mm. The tapered fused region may be provided in such a manner that a plurality of optical fibers are disposed to intersect each other at a predetermined angle, and the intersecting portions are locally heated so as to fuse together and then subjected to pulling. The tapered fused region may be provided at each of two or more positions. Also disclosed is an optical coupler wherein at least one of a plurality of optical fibers each having a core and a cladding is previously heat-treated at a high temperature to enlarge the core in a portion thereof, and the enlarged-core portion of this optical fiber is fused to the other optical fibers and then subjected to pulling, thereby forming a tapered fused region.