Active optical networks (AONs), also called Active Ethernet or Active-E in the world of FTTH networks, utilize traditional Ethernet technologies in a point-to-point star topology.
One or more fibers are dedicated to each end subscriber between the subscriber's premise and the first tier of active Ethernet switching/routing equipment.
This equipment may be distributed and powered out in the field, or it may be colocated at the main distribution point. With AONs, any standard Ethernet fiber optic transceiver may be used now for capacity up to 1 Gbps or even 10 Gbps and eventually up to 40 Gbps and beyond.
If cost is a primary consideration for a new FTTH network project, PONs should be carefully considered. Historically, PONs have been more prevalent in the US, while AONs have been more popular in Europe and Asia.
Because PONs usually require less fiber than AONs, and the average distance between subscribers in the US is larger, PONs are the more cost-effective choice for financing FTTH deployments.
PONs tend to be the least expensive option overall, no matter what the location, especially for larger carriers serving primarily residential markets that have reasonable take rates.
GPON may be the only viable choice if the FTTH project will be deploying analog/digital RF cable TV or traditional voice services (POTS).
GPON is the only cost-effective option that allows these services to be distributed over the same fiber as Internet data to the end subscriber. EPONs and AONs can support IP-based services.
If the FTTH project will be utilizing IP services such as IPTV and voice over IP (VoIP) along with standard Internet data services, then either PON or AON technologies can be used effectively. Other factors would need to be considered in order to make the best choice.
AONs, for example, are gaining in popularity in the US because they can provide increased service flexibility, including better support for media-rich applications requiring high-volume symmetrical bandwidth.
Despite their higher relative costs, AONs can be an excellent option for smaller independent operators that are deploying an all-IP suite of services for voice, data and video, and targeting a mix of customers that may include commercial buildings, academic/government campuses, residential multi-dwelling units (MDUs) and higher-density single-family developments.