Abstract: An optoelectronic semiconductor device for use in an optical transmission system, comprising: an optoelectronic semiconductor element; an element housing which seals covers said element; and an optical fiber arranged through a through hole which is formed in said element housing. An end of said fiber faces said element, while the other end thereof projects out of said element housing by a predetermined length. The device is characterized in that a light absorbing material is disposed around said optical fiber within said element housing. Said material substantially absorbs the light emitted from or received by said optoelectronic semiconductor element.

Abstract: An optoelectronic semiconductor device for use in an optical transmission system comprises a stem for mounting an optoelectronic semiconductor element thereon and a cap within which an optical fiber, optically communicating with the optoelectronic semiconductor element, is arranged. An end of the optical fiber within the cap is exposed on the cap surface. A screw is formed on the outer suface of the cap and a nut, which engages the screw, is provided for optically connecting optical transmission fiber with the optical fiber within the cap.