AON (Active Optical Network) is a signal during transmission, the transmission network from the central office equipment to the use of the photoelectric conversion devices, active optoelectronic devices and fiber optic transmission equipment and other active optical fiber between user allocation unit. Active optical device comprises a light source (laser), optical receivers, optical transceivers, optical amplifiers (fiber amplifiers and semiconductor optical amplifiers).

The so-called optical network is out of the network signal only when electrical / optical conversion and optical / electrical conversion, network transmission and exchange process is always carried out in the form of light. Light is the heart of optical fiber communication. Types and properties of light is good or bad largely determine the type of system, performance and cost.

Early representative network is fiber optic subscriber loop carrier, flexible access system, and PDH / SDH access network of IDLC. Subscriber loop carrier using light as a transmission medium, application pulse code modulation (PCM) technology and optical fiber transmission technology on a pile of road until hundreds of thousands of multiplexed channel telephone, ISDN basic data such as business and other business. Optical fiber subscriber loop carrier and V interface technology, particularly in combination with V5 interface can reduce the cost of the access network.

Currently, there are typically active optical access network is mainly active Ethernet technology, direct access users Bidirectional Point, greatly improving the bandwidth while also increasing the cost. Thus, now active optical access technology is gradually being passive optical access technology (PON) substitution, PON in bandwidth and cost and other aspects of the trade-offs and cost appropriate.