OPTICAL COUPLING DEVICE

摘要

PROBLEM TO BE SOLVED: To optically couple an optical function device of a small spot size and an optical function device of a large spot size or an optical waveguide device by arranging an n-type semiconductor layer of a small refractive index so as to enclose a core layer and a p-type semiconductor layer. SOLUTION: A core layer 101 having the shape or compsn. changing to a tapered form in a light propagation direction is formed on the ridge structure of an n-type semiconductor substrate 102. The p-type semiconductor layer (second clad layer) 103 is formed on the substrate 102 so as to enclose the core layer 101. The n-type semiconductor layers 104 constituting the third clad layer having the refractive index smaller than the refractive index of the second clad layer 103 are arranged on both sides of the core layer 101 via the second clad layer. The p-type semiconductor layers (fourth clad layers) 105 are formed on the core layer 101, a part of the second clad layer 103 and the third clad layer 104. The core layer 101 is arranged in the region enclosed by the substrate 102 and the third clad layer 104.