In this paper, we report the development of a new surface mount structure for optical communication devices using micro-electro-mechanical system (MEMS) technologies. We have designed and fabricated a silicon submount by wet anisotropic micromachining techniques. We have surveyed the main design parameters of this submount as an example against optical and thermal effects by computer simulations and experiments. We have mounted a light-emitting diode (LED) for plastic optical fiber (POF)-based optical communication systems on the silicon submount and evaluated the optical and thermal properties of this submount, indicating that the radiation half width at full maximum (HWFM) angle of the LED decreased from 60 to 40°. Additionally, we have observed a 60% reduction in the thermal resistance of the LED while keeping its thermal reliability.