What is the PON?
PON is the English abbreviation of Passive Optical Network. Because of its large transmission capacity, low maintenance cost and fiber dosage saving, PON has now become the main optical access technology in the world, and is widely used mainly by the fiber to the home (FTTH) network construction. PON is mainly comprised of OLT, optical splitter and ONU. According to the agreement, PON can be divided into EPON, GPON, WDM-PON and so on.
PON has now became a popular network technology all over the globe. It first came in to being in 1995. The International Telecommunication Union (ITU) standardized two initial generations of PON – APON and BPON. And the advancement of PON network has never stopped. Until now, the recent PON standard of NG-PON2 has been put forward in 2015. With the maturity of PON, people are more easily accessible to networks today. But what does PON exactly mean? What’s the composition of PON network? The following part will give you the answer.
PON, also known as passive optical network, is a technology in telecommunication that implements a point-to-multipoint (P2MP) architecture. Unpowered fiber optic splitters are used to enable a single optical fiber to serve multiple end-points such as customers instead of providing individual fibers between the central office (hub) and customer. According to different terminations of PON, the network system can be divided into fiber-to-the-home (FTTH), fiber-to-the-curb (FTTC), fiber-to-the-curb (FTTB), etc. To be specific, a PON is made up of an optical line terminal (OLT) at the service provider’s hub and a number of optical network units (ONUs) or optical network terminals (ONTs) near end users. And “passive” is just used to describe that no power requirement or active electronic component is included for transmitting signals in the system.
Types of PON Network
Here are some types of PON that have been used throughout the years:1) APON
Its full name is asynchronous transfer mode (ATM) passive optical network. As the original PON system, APON uses ATM technology to transfer data in packets or cells of a fixed size. In APON, downstream transmission is a continuous ATM stream at a bit rate of 155 Mbps or 622 Mbps. Upstream transmission is in the form of bursts of ATM cells at 155 Mbps.2) BPON
BPON, also known as broadband PON, is the improved version of APON. It adopts wavelength division multiplexing (WDM) for downstream transmission with the transmission rate up to 622 Mbps. It also provides multiple broadband services such as ATM, Ethernet access and video distribution. Today, BPON is more popular than APON.3) EPON
EPON or Ethernet PON uses the Ethernet packets instead of ATM cells. Upstream and downstream rates of EPON are able to achieve up to 10 Gbps. It is now widely applied to FTTP or FTTH architecture to serve multiple users. With the advantages of scalability, simplicity, multicast convenience and capability of providing full service access, many Asian areas adopt EPON for their networks.4) GPON
Gigabit PON is the development of BPON. It supports various transmission rates with the same protocol. The maximum data rate of downstream is 2.5 Gbps and upstream is 1.25 Gbps. It is also widely used for FTTH networks. But compared with EPON, its burst sizes and physical layer overhead are smaller.
Advantages of PON
- Low cost, simple maintenance, flexible extensibility and easy to upgrade. And no need for power during transmission saves a lot for long-term management.
- Using pure media network avoids the interference of lightning and electromagnetism. Thus PON network is suitable for areas under harsh conditions.
- Low occupancy of central office resources, low initial investment and high rate of return.
- As the P2MP network, PON is able to provide a large range of service to plenty of users.
Conclusion
PON network is for sure an effective solution for multiple network users. EPON and GPON are the most commonly deployed PON systems at present. Since people have been seeking for higher bandwidth provisioning, the capability of transmission will be greatly improved in the near future.
What is the difference between PON and Active Optical Network (AON)?
A Passive Optical Network (PON) uses optical splitters to distribute a single fiber connection from the OLT to multiple ONUs without active electrical components, which reduces power consumption and maintenance. In contrast, an Active Optical Network (AON) uses powered Ethernet switches or routers to manage connections, offering higher bandwidth control but requiring electricity at all distribution points.
How does a PON system work in fiber optic communication?
In a PON system, an Optical Line Terminal (OLT) at the service provider’s central office sends optical signals to multiple Optical Network Units (ONUs) through a passive optical splitter. The OLT allocates time slots for data transmission using TDM, ensuring upstream and downstream communication over a single fiber strand efficiently.
What are the main standards that define PON technology?
PON technologies are defined by standards including ITU-T G.983 and G.984 for BPON and GPON, ITU-T G.987 for XG-PON, and ITU-T G.989 for NG-PON2. EPON is covered under IEEE 802.3ah and 802.3av standards. These standards specify optical budgets, data rates, wavelengths, and transmission protocols.
What are the core components of a PON network?
A PON network consists mainly of an Optical Line Terminal (OLT), passive optical splitters, and Optical Network Units (ONUs) or Optical Network Terminals (ONTs). The OLT connects to the service provider’s backbone, the splitter distributes the optical signal to users, and the ONUs convert optical signals to electrical ones for end devices.
Which PON type should I choose for my fiber network?
For most modern deployments, GPON remains the cost-effective and widely supported option offering 2.5 Gbps downstream. However, for higher capacity and future-proofing, XG‑PON or XGS‑PON, compliant with ITU‑T G.987 and G.9807, are more suitable, providing up to 10 Gbps symmetrical speeds for enterprise or dense urban networks.
