PLC vs FBT Splitter: Differences and How to Choose

PLC and FBT splitters are two types of passive optical devices used to divide an incoming optical signal into multiple outputs. Both perform the same basic function, but their manufacturing technologies, splitting characteristics, and typical applications differ.

Understanding the differences between PLC vs FBT splitters helps internet service providers (ISPs), FTTH installers, network designers, and equipment buyers select suitable optical components.

PLC splitters are widely used in passive optical networks (PONs) requiring multiple equal-power outputs, while FBT splitters are particularly useful for low-port-count applications and customized unequal splitting ratios.

The best choice depends on the required splitting ratio, operating wavelengths, insertion loss, optical power budget, installation environment, and project cost.

What Is an FBT Splitter?

An FBT (Fused Biconical Taper) splitter is manufactured by heating and stretching optical fibers together to form a fused coupling region.

This process allows optical power to be distributed between output fibers.

FBT splitters are commonly used in low-port-count applications, particularly 1×2 configurations.

One important advantage is their ability to provide customized optical power distribution ratios, such as:

• 50:50 — approximately equal power distribution

• 70:30 — unequal power distribution

• 90:10 — unequal power distribution

These percentages describe the nominal distribution of optical power between the output ports, not the overall efficiency of the device.

Actual output power and insertion loss depend on the splitter design, operating wavelength, and manufacturing characteristics.

FBT splitters are useful in optical signal monitoring, selected distribution applications, and systems requiring unequal power distribution.

However, their coupling characteristics can vary with wavelength. Buyers should confirm the specified operating wavelengths before selection.

What Is a PLC Splitter?

A PLC (Planar Lightwave Circuit) splitter uses integrated optical waveguides fabricated on a planar substrate to divide an optical signal into multiple outputs.

Unlike FBT technology, which relies on fused optical fibers, PLC technology uses a waveguide circuit designed to distribute optical power across multiple channels.

PLC splitters are widely used in FTTH and passive optical networks because they support multiple output ports with relatively uniform splitting characteristics.

Common configurations include:

• 1×2

• 1×4

• 1×8

• 1×16

• 1×32

• 1×64

Many telecommunications PLC splitters are designed to operate across a broad wavelength range, commonly 1260–1650 nm, depending on the product specifications.

Their compact optical structure also makes them suitable for integration into fiber distribution boxes, optical distribution frames, and other network enclosures.

PLC splitters are available in different packaging configurations, including Mini, ABS, LGX, and Cassette types.

These terms describe the splitter’s packaging or installation format rather than different optical splitting technologies.

PLC vs FBT Splitter: Key Differences

Although both splitter technologies divide optical power, several technical differences influence their suitability for specific networks.

1. Manufacturing Technology

FBT splitters are produced by fusing and tapering optical fibers.

During manufacturing, the coupling characteristics can be adjusted to achieve the required power distribution ratio.

This makes FBT technology useful for customized low-port-count splitting.

PLC splitters use integrated optical waveguides to divide optical signals across multiple output channels.

This technology is particularly suitable for manufacturing compact devices with higher output counts and consistent splitting characteristics.

2. Splitting Ratios and Port Capacity

FBT splitters are commonly used for 1×2 configurations and other relatively low-port-count applications.

They are especially useful when unequal splitting ratios, such as 70:30 or 90:10, are required.

PLC splitters are commonly available in higher-port-count configurations, including 1×16, 1×32, and 1×64.

This makes PLC technology a practical choice for FTTH networks where one optical input must be distributed to multiple subscribers.

However, the number of output ports should match the network architecture and available optical power budget.

A higher split ratio is not automatically better.

3. Insertion Loss and Uniformity

Insertion loss is one of the most important performance parameters for both PLC and FBT splitters.

Every passive optical splitter introduces signal loss because the incoming optical power is divided among its outputs.

For an ideal equal-power splitter, theoretical splitting loss can be calculated using:

Ideal Splitting Loss (dB) = 10 × log₁₀(N)

Where N is the number of output ports.

These values represent ideal power division losses, not actual product specifications.

Actual insertion loss is higher because of excess loss and other device-related factors, including connector losses where applicable.

For unequal FBT splitters, the expected insertion loss differs between output ports according to the specified splitting ratio.

PLC splitters generally provide good output uniformity across multiple channels, making them suitable for equal-power distribution.

FBT splitters can also provide low insertion loss in suitable low-port-count configurations.

Therefore, PLC splitters do not always have lower insertion loss than FBT splitters.

For a meaningful comparison, evaluate products with the same splitting ratio, operating wavelength, connector configuration, and testing conditions.

4. Operating Wavelengths

Operating wavelength is another important difference between PLC and FBT splitters.

PLC splitters commonly support a broad operating wavelength range suitable for telecommunications applications.

For example, many products are specified for operation from 1260 to 1650 nm.

This can make them suitable for optical access networks using multiple wavelengths for upstream and downstream communication.

FBT splitters may be designed for specific wavelengths or wavelength bands.

Some FBT designs support multiple operating wavelengths, but their coupling ratios and insertion loss may vary outside the specified range.

For either technology, always verify the manufacturer’s wavelength specifications.

5. Cost and Reliability

FBT splitters can be economical for simple 1×2 applications, especially when customized unequal splitting ratios are required.

PLC splitters are often more practical for higher output counts because integrated waveguide technology supports multiple channels in a compact structure.

However, actual pricing depends on:

• Splitting configuration

• Connector type

• Packaging

• Fiber length

• Optical performance requirements

• Order quantity

Both technologies can provide reliable performance when properly manufactured, installed, and maintained.

When evaluating reliability, review the manufacturer’s specifications for operating temperature, insertion loss stability, return loss, polarization-dependent loss (PDL), and environmental testing.

Applicable qualification requirements may reference industry documents such as Telcordia GR-1209-CORE and GR-1221-CORE, depending on the product and project.

Compliance should be verified using the supplier’s supporting documentation rather than assumed from the splitter technology.

PLC vs FBT Splitter Comparison Table

The table summarizes common characteristics. Individual product specifications may differ.

Which Splitter Should You Choose?

The best choice depends on the optical network requirements rather than assuming one technology is universally superior.

Choose an FBT Splitter When

An FBT splitter may be suitable when:

• The application requires a small number of outputs.

• A customized unequal splitting ratio is needed.

• The operating wavelengths match the FBT device specifications.

• A simple low-port-count configuration is preferred.

• The product meets the required optical performance and cost targets.

For example, a 70:30 or 90:10 FBT splitter can be useful when different optical power levels are required at two outputs.

However, the actual insertion loss and output power must be evaluated for the intended wavelengths.

Choose a PLC Splitter When

PLC splitters are generally preferred for FTTH and PON networks requiring relatively uniform splitting across multiple subscribers.

They are especially practical for configurations such as:

• 1×8 PLC splitter

• 1×16 PLC splitter

• 1×32 PLC splitter

• 1×64 PLC splitter

Their compact structure and broad operating wavelength range make them suitable for many passive optical access networks.

In FTTH installations, PLC splitters may be installed inside compatible fiber distribution boxes, depending on the enclosure design, splitter package, and available installation space.

PLC splitters are also available in different packaging formats to accommodate network installation requirements.

Consider the Optical Power Budget

Before selecting a splitter, network designers should calculate the available optical power budget.

The total optical loss includes:

• Splitter insertion loss

• Fiber attenuation

• Connector loss

• Splice loss

• Other passive component losses

• Required engineering margin

A higher splitting ratio increases the optical loss associated with dividing the input signal.

For example, a 1×32 equal splitter has approximately 15.05 dB of ideal splitting loss before additional device-related losses.

Selecting a splitter with more outputs than required may unnecessarily reduce the available optical power margin.

The chosen configuration should support both current subscriber requirements and realistic future expansion.

Key Specifications to Check Before Buying

In addition to choosing PLC or FBT technology, equipment buyers should compare the detailed product specifications.

Choosing the Right PLC Splitter Package

For FTTH projects, the splitter package is often as important as the optical configuration.

Mini PLC Splitter

A compact option that can be integrated into compatible fiber distribution boxes and other enclosures with suitable internal mounting arrangements.

ABS PLC Splitter

Uses a protective housing and is suitable for installations where the specified package dimensions and mounting arrangement can be accommodated.

LGX PLC Splitter

Designed for installation in compatible LGX-format modules, racks, or distribution equipment.

Cassette PLC Splitter

Provides a modular installation format for compatible distribution and termination systems.

The package should be selected according to the enclosure design, available space, connector configuration, and maintenance requirements.

Packaging does not change the basic PLC splitting principle.

Frequently Asked Questions

Is a PLC Splitter Better Than an FBT Splitter for FTTH?

PLC splitters are generally preferred for FTTH and PON networks requiring multiple equal-power outputs.

FBT splitters may be suitable for selected low-port-count applications or customized unequal splitting requirements.

The correct choice depends on the network design and optical specifications.

Does a PLC Splitter Always Have Lower Insertion Loss?

No.

Insertion loss depends on splitting ratio, manufacturing quality, wavelength, connector configuration, and test conditions.

A properly manufactured FBT splitter can provide good optical performance in suitable low-port-count applications.

Can FBT Splitters Provide Unequal Splitting Ratios?

Yes.

FBT splitters can be designed for customized power distribution ratios such as 70:30 or 90:10.

These configurations are useful when different optical power levels are required at different outputs.

What PLC Splitter Ratios Are Commonly Used in PON Networks?

Common PLC splitter configurations include 1×8, 1×16, 1×32, and 1×64.

The appropriate ratio depends on the network architecture, subscriber count, optical power budget, and future expansion plans.

Can PLC Splitters Be Installed Inside Fiber Distribution Boxes?

Yes, provided the splitter package and enclosure are compatible.

Network designers should check available mounting space, cable routing, fiber management, and connector requirements before installation.

Conclusion

PLC and FBT splitters both divide optical signals, but their manufacturing technologies, splitting characteristics, and typical applications differ.

FBT splitters are particularly useful for low-port-count applications and customized unequal splitting ratios.

PLC splitters are widely used in FTTH and PON networks because they support multiple output ports, relatively uniform splitting, and broad operating wavelength ranges.

When comparing PLC vs FBT splitters, consider the required splitting ratio, insertion loss, operating wavelengths, optical power budget, package type, and overall project cost.

Selecting the appropriate splitter helps ensure that the optical distribution network meets its performance, installation, and future expansion requirements.