FTTx, or fiber to the x, is a term used to describe various fiber-optic broadband architectures, where “x” represents the endpoint of the fiber termination. The “x” could stand for a home, building, cabinet, or node-depending on how close the fiber gets to the end user.
Due to its advantages-such as high bandwidth, good network stability, the convenience of management and maintenance, and low cost-the FTTH solutions with PON (Passive Optical Network) configuration has become the current preferred network access solution.
PON is a P2MP (Point to Multiple Point) network architecture comprising OLT (Optical Link Terminal)-the central hub managing data transmission, ODN (Optical Distribution Network)-the passive fiber infrastructure, and ONU (Optical Network Unit)-the endpoint device at user premises.
With the downstream optical signal wavelength set as 1490nm and the upstream optical signal wavelength at 1310nm, optical signals can be transmitted simultaneously over the same fiber using WDM (Wavelength Division Multiplexing) technology. Data is broadcast for downstream transmission and uses TDM (Time Division Multiplexing) for upstream transmission, enabling P2MP communication.
Currently, there are two main PON access network solutions: GPON (Gigabit-Capable PON) and EPON (Ethernet Passive Optical Network). GPON is the most widely adopted solution for FTTH deployment due to its efficientt bandwidth utilization and scalability. EPON, on the other hand, operats on a single Layer 2 network that carries data, voice and video over IP. It provides symmetrical bandwidth of 1 Gbit/s or 2.5 Gbit/s and is generally more cost- effective than GPON.
