The Passive Optical Network (PON) is the optical fiber infrastructure of the FTTH network. The first crucial point in the architectural decision for the Passive Optical Network (PON) is that of optical splitter placement according to customer demand.The Passive Optical Network (PON) splitting may be achieved by centralized splitting (one level) or by cascaded splittings (two-level or more). A centralized approach typically uses the splitter 1×64 and it is located in a fiber distribution hub (FDH). The splitter is directly connected through a single fiber to an OLT in the central office of the telecom operators. On the other side of the splitter, 64 fibers are provided to 64 customers’ homes, where it is connected to an optical line terminal (ONT). Thus, the Passive Optical Network (PON) connects one OLT port to 64 ONTs.

In the PON network, there are two common splitter configurations—centralized approach and cascaded approach.

A cascaded approach may use a 1×4 splitter residing in an outside plant enclosure. This is directly connected to an Optical Line Termina (OLT) port in the central office of the telecom operators.Each of the four optical fibers leaving this lever-1 splitter is provided to an access terminal that houses to a 1×16 level-2 splitter. In this scenario, there would be a also total of 64 optical fibers (4×16) reaching 64 homes customers. This is possible to have more than two splitting levels in a cascaded system.
In the other hand, two-level and multi-level cascaded splitting solution is used in small town or village places, to cover widely ODN nodes of the FTTH network, conserve resources and save the money.

A centralized approach of FTTH Network typically offers greater flexibility, minimized operational costs and easy to access for the technicians. A cascaded systems approach may yield a faster return-on-investment with lower first-in and optical fiber costs. Usually, the centralized splitting solution is used in crowded metro city center or town areas, in order to reduce cost of network and easy to maintain the optical distributed network (ODN) nodes.

The centralized splitter approach typically uses a 1×32 splitter in an outside plant (OSP) enclosure, such as a fiber distribution terminal. The 1×32 splitter is directly connected via a single fiber to an OLT in the central office. On the other side of the splitter, 32 fibers are routed through distribution panels, splice ports or access point connectors to 32 customers’ homes, where it is connected to an ONT. Thus, the PON network connects one OLT port to 32 ONTs.