1x8 Plc Splitter

Application of PLC splitter in PON network?

PLC splitters are the core optics in passive optical network (PON) systems, widely used in fiber-to-the-home (FTTH), which has two different distribution methods in FTTH networks: centralized distribution and cascade distribution.

Centralized distribution

Centralized distribution means that the optical splitter between the optical line terminal (OLT) and the optical network unit (ONU) is parallel, and the basic manifestation is "OLT→ optical splitter →ONU", where the splitting ratio of the optical splitter is usually 1:32. In a centralized distribution, optical splitters are centrally distributed in the fiber distribution box and directly connected to the OLT at the central central office through a single fiber, and the other end is connected to multiple ONTs on the user side through multiple fibers. Its use is generally divided into four situations:

1. Place in the central computer room;

2. Place in the community computer room;

3. Put it in the light handover box of the community;

4. Placed directly in the corridor.

Centralized distribution has the advantages of high flexibility, low cost and convenient maintenance, and is generally suitable for use in urban centers or towns with a high concentration of users.

Cascading distribution

Cascade distribution means that the optical splitter between the optical line terminal (OLT) and the optical network unit (ONU) is cascaded, and the basic manifestation is "OLT→ optical splitter 1→ optical splitter 2→ONU", where the splitting ratio of optical splitter 1 is usually 1:4, and the splitting ratio of optical splitter 2 is usually 1:8. In a cascaded distribution, optical splitter 1 is usually installed near the central office and optical splitter 2 is usually installed near the user end, such as in a corridor. Its use is generally divided into three situations:

1. The primary optical splitter is placed in the central computer room, and the secondary optical splitter is placed in the optical handover box of the cell;

2. The primary optical splitter is placed in the cell computer room, and the secondary optical splitter is placed in the cell optical handover box;

3. The primary optical splitter is placed in the optical handover box of the community, and the secondary optical splitter is placed in the corridor.

Cascade distribution has the advantages of low user access cost and flexible adjustment of optical splitting ratio, and is generally suitable for use in villages with scattered users.

What is the comparison between centralized and cascading distributions?

Centralized distribution network

The centralized distribution generally adopts a combined distribution ratio of 1:64, a 1:2 splitter at the central office, and a cabinet of 1:32. These single-stage fiber splitters can be placed in multiple locations in the network or installed in a central location. But in most cases, centralized fiber splitters are placed in external equipment (OSPs) to reduce the total amount of fiber required. OLT (Optical Line Termination) active ports in the central office (CO) will connect/splice to the fiber leaving the CO. This fiber is reached through different closures to the input port of the fiber splitter, which is usually placed in the cabinet. The output port of this fiber splitter enters the FTTH distribution network and reaches the home of the potential customer through different closed devices and indoor/outdoor terminal boxes called ONTs (Optical Network Terminals). Therefore, in this centralized split topology, PON connects one OLT port to 32 ONTs.

Cascading distribution

Unlike centralized tap topologies, the cascade tap method does not have fiber splitters in the central office. The OLT port is directly connected/spliced to an external plant fiber. The first stage diverter (1:4 or 1:8) is installed in an enclosed place not far from the central office. The input of the first-stage fiber splitter is connected to the OLT fiber from the central office. The second stage fiber splitter (1:16 or 1:8) is located in a terminal box, very close to the customer's location, and each splitter covers 8 to 16 homes. The input to these PON splitters is the fiber from the output of the first stage splitter described above.