Semiconductor element module

Claim 1

A semiconductor element module comprising: a sleeve having a first hollow portion defining a first open end thereof, which hollow portion extends toward an interior portion of said sleeve wherein, a ferrule for positioning an optical fiber is adapted to fit in said first hollow portion, a second hollow portion defined in a second end of said sleeve, said second hollow portion being coaxial with the first hollow portion and formed having a second open end which is opposite to said first open end, said second hollow portion extending toward the interior portion of said sleeve, and a third hollow portion formed to link the first and second hollow portions, said sleeve consisting of a metal selected from the group consisting of ferrite-based stainless steel, SUS430-based metal, SUS430F metal, and a metal having characteristics corresponding to that of ferrite-based stainless steel, SUS430-based metal, and SUS430F metal; a stem hermetically fixed to said sleeve and sealing the second open end thereof; an optical active element fixed on a surface of said stem; and a converging lens, housed in the third hollow portion and hermetically fixed to said sleeve in order to seal said third hollow portion, for optically coupling an end face of said optical fiber to a light-emitting or light-receiving end face of said optical active element, wherein said sleeve is integrally formed using said metal having a thermal expansion coefficient which has a correlation expressed by the following equation with a thermal expansion coefficient of a material constituting said converging lens: (k.sub.1 -k.sub.2)/k.sub.1 <30% k 1 : a thermal expansion coefficient of the sleeve k 2 : a thermal expansion coefficient of the lens.