GPON, or Gigabit Passive Optical Network, is a widely adopted point-to-multipoint fiber network architecture used to provide broadband services to both residential and business users. It utilizes passive splitters in the fiber distribution network, allowing one single feeding fiber from the provider to serve multiple homes and businesses.

Here’s a closer look at GPON:

Key Components:

  • Optical Line Terminal (OLT): Located at the service provider’s central office, this device sends and receives the optical signal to multiple premises.
  • Optical Network Terminal (ONT) or Optical Network Unit (ONU): Devices installed at the user’s location. They convert optical signals from the OLT into electrical signals for user devices.
  • Optical Splitter: Passively splits one optical signal from the OLT into multiple signals to serve different ONTs/ONUs.

Features:

  • Downstream Bandwidth: Typically up to 2.488 Gbps.
  • Upstream Bandwidth: Typically up to 1.244 Gbps.
  • Wavelength: GPON uses 1490 nm for downstream and 1310 nm for upstream.
  • Distance: Can cover distances up to 20 km or more.
  • Split Ratio: Common split ratios are 1:32 or 1:64, meaning one fiber from the OLT can serve 32 or 64 ONTs/ONUs.

Protocol:

  • GPON leverages the ITU-T G.984 series standards.
  • It employs ATM (asynchronous transfer mode) and GEM (GPON encapsulation mode) to transport data.

Advantages:

  • High Bandwidth: Can accommodate high-speed internet, VoIP, and IPTV on a single connection.
  • Efficiency: Uses bandwidth dynamically, allocating based on user demand.
  • Economical: Passive splitters mean no power requirement in the distribution network, resulting in cost savings.
  • Long Reach: Effective for both urban and more extended rural connections.
  • Scalability: Can serve a significant number of users with a single OLT.

Applications:

  • Triple Play Services: Delivering voice, video (TV), and data services on a single fiber connection.
  • High-Speed Internet: For residential and business users.
  • Backhaul: For mobile LTE and 5G base stations.

Comparison with EPON (Ethernet PON):

  • EPON, based on the IEEE 802.3 standard, uses Ethernet packets, whereas GPON can use various packet types.
  • EPON typically offers symmetric 1 Gbps upstream and downstream, while GPON provides asymmetric speeds.

Evolution:

  • Newer technologies like XGS-PON (10-Gigabit-capable symmetric passive optical network) and NG-PON2 (Next-Generation Passive Optical Network 2) are evolving from GPON, offering higher speeds and capacities.

GPON is widely used by telecom operators worldwide to offer fiber-to-the-home (FTTH) services, ensuring that users get high-speed and reliable internet connectivity.