| 摘要 |
PURPOSE:To improve the coupling factor between a light emitting device and an optical fiber by a method wherein the distance between the light emitting surface of a light emitting part and the tip of the cylindrical part or the spheri cal part of a lens layer is reduced. CONSTITUTION:A trench 2 with a trapezoid cross section is formed in the surface of an n-type InP substrate 1. An n-type InP buffer layer 3 is built up on the substrate 1 and a trench 4 with a circular arc cross section is formed in its surface. Further, an n-type InGaAsP lens layer 5 is built up on the layer 3 and its surface is made to be flat and an n-type InP cladding layer 6, a p-type InGaAs active layer 7, a p-type InP cladding layer 8 and a p-type InGaAsP cap layer 9 are built up. At that time, the forbidden bend width of the layer 5 is so selected as to be larger than that of the layer 7 and the refractive index of the layer 5 is so selected as to be larger than those of the layers 6 and 3. With this constitution, the distance between the light emitting surface of the light emitting part 10 and the tip of the cylindrical part or the spherical part of the layer 5 can be reduced so that the coupling efficiency between the light emitting device and an optical fiber can be improved. |
