Optical transmission module

摘要

A semiconductor laser 1 and an optical fiber 4 are optically coupled via a first lens 2 and a second lens 3, the second lens is previously fixed to a module package 5 and the parts are mounted to the module package, when focal lengths of the first lens and the second lens are respectively designated by f1 and f2, an optical distance d between a principal plane 32 of the first lens on its side facing the second lens and a principal plane 33 of the second lens on its side facing the first lens, is made substantially equal to f1+f2. Thereby, there is provided an optical transmission module having low price capable of achieving a high coupling efficiency with high yield. <IMAGE>