Optical splitter is an essential part of PON network. The famous passive optical network structure“point to multipoints” of PON network is formed by optical splitter which evenly distributes light power in the direction of downstream and aggregates the light power in the upstream direction. The major function of optical splitter is to provide transmitted path of light-medium for OLT in network end and ONU in user end. 

Working principle of optical splitter

There are two types of optical splitter so there are two ways of working modes, FBT splitter and PLC splitter. FBT splitter is to weld two or more fibers, PLC splitter completes the light distribution by forming light waveguide on media or semiconductor substrate via photoetching technique. Basically, it’s the same principle of light distribution for these two types of optical splitter, that is, by changing evanescent field between fibers and radius of fibers to accomplish different amounts of distribution. 

Category of optical splitter

By the form of ports, optical splitter could be categorized into “star” shape of optical splitter and “tree” shape of optical splitter. If the amount of input ports is equal to the amount of output ports, it can be identified as star optical splitter. And if not equal, it’s tree optical splitter. In PON network, tree optical splitter is used and normally written as “MxN”, M stands for the amount of fiber path inputted, N means the amount of fiber path outputted. M mostly is 1 or 2, N sometimes is 2, 4 or 8, 16, 32,64,128 or others.

Application of optical splitter in PON network

PON network is the key of FTTX, in the deployment of FTTX, there are several typical schemes of light distribution by optical splitter, and they are considered as low cost and easy maintenance.

1. Scattered light distribution solution for high-rise buildings 

This solution is suitable for the condition when the users in high-rise building are relatively scattered and the amount is small. Light power could be distributed as long as put the optical splitter between distribution fiber optic cable and drop fiber optic cable.

2. Centralized light distribution solution for high-rise buildings  

This solution is suitable for the condition when the users in the high-rise building are relatively concentrated and the amount is large. Optical splitter functions as long as it is placed between trunk cable and distribution cable. 

3. Light distribution solution for among multiple buildings

In this way optical splitter is placed in the optical cable connecting cabinet to accomplish the first distribution, and after the distributed cables are pulled into buildings, then introduce the fibers to ONT/ONU by fiber distribution box. 

Conclusion

Optical splitter acts in PON network as a key to a door, and of course, it plays an important role in other applications. Knowing how it works and its advantages will greatly help to find an efficient solution to network deployment.