Fiber Splitter PON network

Comparison Between FBT Splitter and PLC Splitter

To cope up with modern day fiber optic network’s needs and stringent requirements on performance, security, safety and modularity, many new technologies and high-performance equipment are needed. Fiber optic splitter, which can distribute and combine energy with low cost and high reliability, is one of them. Generally, based on different working principles, optical splitter can be divided into two types—FBT splitter and PLC splitter. Many people may wonder what differences between them and which one we should choose for our project. To better understand these two splitters, the following part will make a comparison between them.

Basic Concept of FBT Splitter and PLC Splitter
FBT Splitter

Based on traditional technology, FBT (fused biconical taper) splitter contains two fibers which are placed closely together, typically twisted around each other and fused together by applying heat while the assembly is being elongated and tapered. It is made out of materials that are easily available, such as steel, fiber, hot dorm. All of these materials are low-price, making the device itself inexpensive. With its low cost and easy installation, FBT splitters are widely adopted in passive networks, especially for instances where the split configuration is smaller (like 1×2, 1×4, 2×2, etc.). The following image shows a 1×2 FBT splitter.

1×2 FBT splitter

PLC Splitter

PLC (planar lightwave circuit) splitter is the recent addition in fiber optic technology to exhibit uniform signal splitting among the most advanced optical networks. PLC splitter is a fully passive optical branching device that is based on planar light wave circuit technology and precision aligning process, which can evenly split or distribute a single optical signal/input into many outputs with high accuracy and minimal loss in an efficient manner. PLC splitter is a high-quality device, especially for passive internet (EPON, GPON, BPON). Here is a picture of 1×16 PLC splitter.

1×16 PLC splitter

Differences Between FBT and PLC Splitter

There are many differences between FBT and PLC splitter, and the following part will put more emphasis on the aspects of fabrication method, operating wavelength, splitter ratio, size of splitter and cost.

  • Fabrication Method: For FBT splitter, there are two or more pieces of optical fibers bound together inside the fused-taper fiber device. The fibers are then drawn out according to the output branch and ratio with one fiber being singled out as the input. PLC splitter consists of one optical chip and several optical arrays depending on the output ratio. And the optical arrays are coupled on both ends of the chip.
  • Operating Wavelength: FBT splitter only supports three wavelengths (850 nm/1310 nm/1550 nm) which makes this device less customizable for different purposes, but PLC splitter can operate over wavelengths from 1260 nm to 1650 nm, covering various PON standards, so it can be applied for a variety of applications.
  • Split Ratio: A split ratio is the amount of light that is re-directed from the network to the monitor ports. The higher the split ratio, the better the performance. The split ratio of FBT splitter is up to 1:32, while the ratio of PLC splitter goes up to 64, which can provide a higher reliability.
  • Size: FBT splitter, which utilizes traditional technology, is much bigger in size and cannot easily fit in all cabinet. Compared to FBT splitter, PLC splitter is much more compact and can save more space. Hence, it is more suitable for density applications.
  • Cost: As we have mentioned above, FBT splitter is normally made by low-price materials, like steel or fiber, thus it has low cost than PLC splitter. Besides, the technology of the device manufacturing is relatively simple, which has the impact on its price as well. But for PLC splitter, it uses more complex semiconductor technology (lithography, etching, developer technology) production, making the price of this device higher.
Summary

Besides the differences that we have discussed above, there also exists many other differences between this two types of optical splitter, such as the spectral uniformity, temperature dependent loss,and the input/output fibers, etc. Both of these splitters have their own advantages upon different aspects. From this post, hope you can get a basic understanding of FBT and PLC splitter and next time when you choose optical splitter, you won’t feel confused.

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