Optical Access Network refers to the optical fiber as the transmission medium of the network environment. Technically fiber access network can be divided into two categories: active optical network (AON) and passive optical network (PON). Active optical network can be divided into SDH and PDH's AON; passive optical network can be divided into narrowband and broadband PON.

Since the optical fiber access network transmission medium is an optical fiber, therefore, according to fiber deep level user group can be divided into fiber access networks FTTC (fiber to the curb), FTTZ (fiber to the community), FTTB (fiber to the building), FTTO (fiber to the office) and FTTH (fiber to the home), which are collectively referred to as FTTx. FTTx does not refer to a specific access technology, but refers to the optical fiber access network to promote the level or usage policies.