OLT (Optical Line Terminal), ONU (Optical Network Unit) devices, and passive splitters. Passive optical splitters typically split the signal up to 64, allowing the use of only one fiber optic cable connecting the Internet service provider with multiple end users.
So how does
the whole process work? In simple terms, it goes like this:
• First, the
optical line terminal transmits data in the form of optical signals through a
process called optical wavelength division multiplexing (WDM). The OLT is
usually an ISP and can be thought of as the starting point of GPON.
• The signal
propagates on a single optical fiber through the Optical Distribution Network
(ODN) and finally reaches a passive splitter. GPON fiber optic networks can
reach distances of up to 20 km.
• The
passive GPON splitter receives the optical signal and splits it into up to 64
multiple signals. This allows point-to-multipoint access and up to 64 fiber
optic connections.
• Finally,
the last mile split optical signal reaches individual GPON ONT/ONU devices
installed on the premises of a residential or commercial building. This is the
endpoint of GPON, which can convert optical data signals to electrical signals.
Conversely, data is transmitted upstream from GPON ONT/GPON ONU to OLT.
GPON has
another great feature: it integrates voice and data traffic on the same network
using Asynchronous Transfer Mode (ATM) coding. After all, GPON is very useful today
to securely deliver triple play services (data, IPTV, VoIP) at higher data
rates, higher bandwidth, and longer distances. GPON also supports all types of
Ethernet protocols.
How does GPON work?
Now that we
have a good understanding of GPON, it is natural to try to understand how it
works. The key to GPON's operation is its point-to-multipoint access fiber
network topology.
