PON (Passive Optical Network)

PONs are short-range optical fiber networks that are used to provide Internet, VoIP and television services.
They are also used in infrastructure connections in cellular base stations, WIFI hotspots, and DAS (distributed antenna systems).
PON is a fiber-optic network. Instead of active equipment such as repeaters, shaping circuits and amplifiers, they use passive equipment such as splitters and combiners.
The coverage range of a PON network is about 20 km, while the coverage range of an Active Optical Network or AON network is about 100 km.

Examples of PON

Examples that use optical fiber all the way from the server to the client.

  • FTTH
  • FTTP
  • FTTB

Those that do not use optical fiber to reduce the cost all the way from the server to the client.

  • FTTC
  • FTTN

PON configuration

  • OLT
    PON is a point to multipoint network in which an OLT or Optical Line Terminal sends the desired services to 6 to 128 customers per optical fiber.
  • ONU
    Optical network unit (ONU) is a device that communicates with an optical network terminal called ONT, which transmits PON to wireless router, computer, phone or TV.
  • ONT
    A device that connects ONU with Wireless router and Computer etc.
  • Optical splitters
    In PON, optical fiber splitters are devices that divide a single optical signal into several equal parts with weaker power and distribute them to users.

In the basic operation method for downstream distribution in one optical wavelength from OLT to ONU or ONT, all receivers receive the same data.
And it is the duty of the ONU to recognize the targeted data of each user.

For upstream distribution from ONU to OLT, TDM or Time Division Multiplex technology is used. That each user is assigned a reliable output on different wavelengths of light, in which splitters act as power combiners.
Upstream communication is randomly performed based on the needs of the users, which allocates a slot to the user according to the needs. Because the TDM method involves multiple users on a single transmission system, the upstream data rate is always slower than the downstream.



At the end of 1990, the International Telecommunication Union introduced the APON standard, which used ATM or Asynchronous Transfer Mode to transmit data packets over long distances.
After that, the BPON was introduced, which offered a speed of 622 mbits/s in the DOWNSTREAM and 155 mbits/s in the upstream.
The next standard was called GPON or Gigabit PON, which offered a speed of 482 Gbits/s in the downstream and 1.244 Gbits/s in the upstream.
While each ONU uses the entire downstream rate of 2.488 Gbits/s,
GPON uses a time division multiple access or TDMA to allocate specific time efficiency to each user.
This bandwidth division is such that each user’s share is a fraction of 100 Mbits/s.
Each fiber provides service to 32 to 64 users, which increases to 128 users in some systems.
GPON uses an encapsulation method to transport protocols that can encapsulate Ethernet, IP, TCP, UDP, T1/E1, video, VoIP, or other protocols called data transmission. The latest version of GPON is a 10-gigabit version named XGPON. as the demand for video and television services has increased, the need to handle the huge amount of high-quality video data that XGPON can handle has also improve

Rate this page