SEMICONDUCTOR DEVICE

PURPOSE:To arrange a laser diode and a light-receiving element on the same plane and to contrive the improvement of productivity and a reduction in the cost by a method wherein, with the laser diode and the light-receiving element arranged on the same plane, a plurality of reflecting plates are provided between this laser diode and the light-receiving element. CONSTITUTION:A laser diode 1, a light-receiving element 5 and a first reflecting plate 13a are mounted on a substrate 11. The laser diode 1 and the light- receiving element 5 are each connected electrically to wiring patterns 12 through lead wires 6a and 6b, respectively. The first reflecting plate 13a is arranged in such a way as to form an optical path between the laser diode 1 and the light-receiving element 5. One of laser beams 10a and 10b from the laser diode 1 is deflected by the reflecting plate 13a or 13 and is introduced to the light- receiving surface of the light-receiving element 5 mounted on the same plane along with the laser diode 1. By this way, the output of the laser diode 1 can be monitored and adjusted. It is thus possible to arranged the light-receiving element on the same plane along with the laser diode.