MOUNTING STRUCTURE OF PHOTODETECTION MODULE

PURPOSE: To protect an optical transmission module against an external electromagnetic induction noise and to prevent the module from malfunctioning by electrically connecting a metal cover, which holds a plastic case, to the case of the optical transmission module. CONSTITUTION: The photodetection module can be fixed to the optical transmission module by joining the slit in the flank of the plastic case 2 to the cut part of the case 4 of the optical transmission module. The metal cover 3 and the case 4 of the optical transmission module are made of metal which effectively shields the module from an external electromagnetic wave noise. After the plastic case 2 is fitted to the case 4 of the optical transmission module, the metal cover 3 is made to butt against the case 4 of the optical transmission module and fixed by soldering to the butting part, so that the both are electrically connected together. Consequently, the part from the housing 4 to the photodetection module body covered with the metal cover 3 has electromagnetic wave shield performance.