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What are Active (AON) and Passive (PON) Optical Networks?

(Last Updated On: April 24, 2023)

We hear a lot about fiber optic networks for broadband internet, but there’s more than one way they can be constructed.

While the leading network will always be fiber, there are alternatives as to how to connect the ‘last mile’ – the few hundred meters nearest the consumer’s home or the business premises of the end user. This may use fiber to the home (FTTH) or curb (FTTC), where the last few meters are handled with copper cables – together, these variants are known as FTTx.

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Fiber to the home (FTTH) is a system which installs optical fiber from a central point directly to individual buildings such as residences and apartments. The deployment of FTTH has come a long way before subscribers adopt optical fibers instead of copper lines to achieve broadband Internet access. There are two basic paths to deploy high-speed FTTH networks: active optical network (AON) and passive optical network (PON). Then AON vs PON networks: what exactly are the differences between PON and AON? To get a better understanding, let’s take a closer look to see which one can help you achieve the desired performance for your network.

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AON is a point-to-point network structure in which each subscriber has its fiber-optic line terminated on an optical concentrator. AON network covers electrically powered switching equipment, such as a router or a switch aggregator, to manage signal distribution and direction signals to specific customers. The switch directs the incoming and outgoing signals to the proper place by opening and closing in various ways. The reliance of the AON network on Ethernet technology makes interoperability among vendors easy. Subscribers can select hardware that delivers an appropriate data transmission rate and scale up as their needs increase without the need to restructure the network. However, the AON network requires at least one switch aggregator for each subscriber.

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Unlike AON networks, PON is a point-to-multipoint network structure in which passive optical splitters are used to separate and collect optical signals. The fiber optic splitters allow the PON network to serve multiple subscribers in a single optical fiber without the need to deploy individual fibers between the hub and the end users. As its name shows, the PON network does not include electrically powered switching equipment and shares fiber optic strands for portions of the network. Powered equipment is required only at the source and receiving ends of the signal.

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Comparison Between AON and PON

Following are a few of the comparison points between AON and PON:

  • In PON, Bandwidth allocation per subscriber is estimated based on the splitting factor. In AON, the allocation amount depends on the interface type and is adjustable. Hence AON type has the advantage over PON as far as bandwidth allocation is concerned.
  • The impact of faults in the access node is low in AON compared to PON.
  • The reliability of the subscriber line (between customer-AN-Passive Splitter) is good in AON compared to PON.
  • The reliability of the subscriber line (between passive Splitter and OLT) is good in PON compared to AON (between AN and Edge Switch).
  • The costs of passive components used in PON are lower than those of active components used in AON. Hence PON has the advantage over AON as far as cost is concerned.


All systems have their specific advantages and disadvantages. Those who subscribe to AON can benefit from the fact that bandwidth in each port is dedicated to each subscriber, and they don’t need to share the bandwidth with anyone. So you can have a much higher bandwidth per port through AON than with PON. Also, it is much simpler to identify defects in the AON. The drawback of the AON system is that it needs active equipment for managing signal transmission. So the electricity costs can be high.

Signal Distribution

You can have a dedicated fiber optic strand as a subscriber to an AON network. This means each person subscribes to AON gets dedicated bandwidth that isn’t shared. Users of PON can share the fiber optic strands for a part of the network. Since you have different structures for PON, the results will also be different. So if there is an issue with the PON network, you won’t be able to find the source of the problem. This is not an issue with AON.

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AON directs optical signals by making use of electrically powered equipment. There is no powered equipment used in PON except for those used to guide signals to the two ends of the system. The biggest ongoing expense in a network is powering equipment and maintenance. PON uses passive components that require less maintenance but no power. So PON is less expensive than AON.

AON networks are long-range and can cover a distance of 100 km. PON is the short-range network that can up to no more than 20 km. For running PON, subscribers have to be nearby the central source of the data. AON and PON are two different solutions for FTTH networks. Both systems are widely used because of the huge demand for more bandwidth.

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In most countries, it’s simply too expensive to run a dedicated or direct fiber link to each subscriber. If there is already existing copper telephone cable running to each home, it will be cheaper to use that for the last few meters, which makes the connection slower.

There are a lot of discussions about which fiber network architecture to adopt for your fiber network deployment. At its core, a rugged fiber network strategy is a best practice that should be a part of every company’s day-to-day operation. So, how should our network be constructed, so that fast fiber can reach all the way to the end user, but without the prohibitive cost of everyone having their own private connection? —— Please choose HOLIGHT!

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