This paper focuses on the composition and key technology of 10 Gbit/s EPON asymmetric ONU optical modules

especially on the structure of the emitting hardware circuits and the principle of the digital Automatic Power Control（APC）

introduces the realization of the receiver section and gives a rational design scheme

which is verified in experiments.The results indicate that the optical modules designed in this scheme conform to the requirements of the international standards and can be extensively applicable in the flied of optical communications.