LIGHT SOURCE-OPTICAL FIBER COUPLER

摘要

A light source-optical fiber coupler constituted by: a light source (such as a semiconductor laser chip 10); and a gradient index rod lens 14 for coupling diffuse luminous flux emitted from the light source to an end surface of an optical fiber (such as a single mode optical fiber 16) . The gradient index rod lens has a light source side end surface shaped like a convex spherical surface, and an optical fiber side end surface shaped like a flat surface. The gradient index rod lens is retained by the housing in the condition that the light source (laser chip) and the gradient index rod lens are disposed close to each other. The distance between a surface of the laser chip and an end surface of the gradient index rod lens is preferably selected to be not larger than 0.3 mm and more preferably in a range of from about 0.2 mm to about 0.25 mm.