Brief Introduction of Fiber Optical Splitters

Fiber optic splitters are quite important in today’s optical network. Splitters can help users maximize the functionality of optical network circuits. A fiber optical splitter is a passive optical device that can split, or separate, an incident light beam into two or more light beams. These beams may or may not have the same optical power as the original beam. The outputs of a splitter can have various degrees of throughput. And that is very useful to decide whether the splitter is used for network monitoring or for a loss budget in a passive optical network (PON) architecture when designing optical networks. This article will give brief introduction of fiber optical splitter.

Two Types of Fiber Optical Splitters

There are two kinds of the most commonly used fiber optical splitters. And they are planar lightwave circuit (PLC) and fused biconical taper (FBT). PLC splitters (as shown in the following picture), from the name, it’s easy to find out that PLC splitters are based on planar lightwave circuit technology. It uses an optical splitter chip to divide the incoming signal into multiple outputs. It consists of three layers including a substrate, the waveguide, and the lid. The waveguide layer accepts the incoming optical signal and passes it to the outputs. FBT splitters are fused with a heat source similar to a fusion splice. Fibers are aligned in a group to create a specific location and length and will be fused with heat to meet the desired parameters such as insertion loss. Fused fibers are put in a V-shaped groove and fixed in a silica tube with a mix of epoxy and silica powder to get the proper heat.


Fiber Optical Split Ratios

Fiber optical splitters vary in numbers of inputs and outputs. The split ratios are based on the network use of fiber optical splitters. In a PON architecture, it uses splitters to split a single fiber into multiple fibers to feed as many as 64 end users. A typical split ratio in PON application is 1:32, or one in coming fiber split into 32 outputs.

Large split ratios like 1:32 or 1:64 are often found in some kind of housing. That’s because with so many fibers related to these splitters, a platform should be used to manage the splitter modules, patch modules, patch cables, etc. Most often a high-density fiber bay is required so that the splitters can be all placed in a distribution site or a PON enclosure. The PON cabinet plays a significant role in today’s applications since the space is so limited. When it comes to a high-density frame with varying split ratios and large number of patch cords, the distribution frame is critical for a good cable management.

Cost Saving in FTTx/PON Applications

As the city grows and subscribers increase, the network architect must deal with multiple distribution points and backhaul. To meet so many subscribers’ requirements, the flexibility in head-end locations, distribution points and split ratios becomes more significant. To network service provider, saving capital and operational costs is important.

On one side, fiber optical splitters can save fiber cost by reducing the fiber usage and that’s why they are so important in FTTx/PON networks. Using a single fiber to feed as many as 64 end users significantly reduces the fiber quantity. On the other side, the long-term operation costs can’t be ignored either in optical network splitter applications. That’s one of PON’s advantages. For example, it can decrease the power consumption.

Another way to save cost is to ease maintenance and increase the flexibility for smaller split ratios, which lead to more bandwidth per subscriber. For example, a service provider would likely need to split the optical terminal line (OLT) with a 1:2 splitter, and adjust the split ratios from there based on delivery to residential (1:32). These multiple split ratios can create flexibility in the network as long as the utilization of transport electronics such as OLT is concerned. Loss budget can be greatly influenced by the use of multiple splitters.


From the above content, to run a network architecture, the network success and cost should be paid attention. And fiber optical splitter is such a good device to increase the efficiency of optical infrastructure and save the capital and future operational cost.

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