Light branching and coupling device

摘要

A light branching and coupling device excellent both in transmitting performance and in distributing performance in which the intermediate portion of an optical fiber 10a (10b) is thermally drawn to form light transmission fiber portions 11a and 15a (11b and 15b) and a light branching and coupling fiber portion 13a (13b) having a diameter smaller than that of the light transmission fiber portions and, at the same time, form tapering fiber portions 12a and 14a (12b and 14b) between the light transmission fiber portions and the light branching and coupling fiber portion so that the tapering fiber portions are tapered off gradually toward the light branching and coupling fiber portion 13a (13b) side. The light branching and coupling fiber portions 13a and 13b thus formed are fused with each other.