Patent ID: 7335875
Filing Date: 2008-02-26
Classification: G02B

Abstract:
1. An optical branching unit comprising: a light input part which inputs light; an optical branch which branches the light input to the light input part at a predetermined ratio; a light output part which guides the light branched by the optical branch to a predetermined position; an adhesive layer which is formed to a predetermined thickness on the light input part, the optical branch and the light output part; a substrate which holds the light input part, the optical branch and the light output part; a cover member which covers the light input part, the optical branch and the light output part on the substrate through the adhesive layer; and a stress equalizing member which is provided on the substrate independently of the light input part, the optical branch and the light output part, and which prevents a stress generated when the adhesive layer is hardened from acting on any one or all of the light input part, the optical branch and the light output part on the substrate, wherein the stress equalizing member has an area so that an occupation rate, defined as a total area of the stress equalizing member and the light input part, the optical branch and the light output part relative to a total area of the substrate, is at least 70%.