Patent ID: 7183581

Claim:
An optical transmission module comprising: a light-emitting device; a light-receiving device operable to directly receive backward light emitted from the light-emitting device; a driving device operable to drive the light-emitting device; and a substrate on which the light-emitting device, the light-receiving device, and the driving device are arranged, wherein the light-receiving device is disposed directly on the substrate, and the driving device is entirely disposed between the light-emitting device and the light-receiving device so as to be lower than a straight line connecting a backward light emitting point of the light-emitting device and a backward light receiving point of the light-receiving device, said driving device not contacting said light-receiving device but electrically connecting with said light-receiving device, wherein a concave section is formed in a surface of the substrate between the light-emitting device and the light-receiving device, and the driving device is disposed on a bottom surface of the concave section.