Why Fiber Optic Splitter Loss Table Is So Important?

A fiber optic splitter divides an optical signal into multiple output paths, making it an essential passive component in FTTH and passive optical networks (PONs).

However, splitting an optical signal also reduces the optical power available at each output port. A fiber optic splitter loss chart helps network engineers understand how optical loss changes with different split ratios.

This guide explains theoretical splitting loss, insertion loss, excess loss, and how to use a splitter loss chart when evaluating optical power budgets.

What Is a Fiber Optic Splitter Loss Chart?

A fiber optic splitter loss chart provides reference values showing the relationship between the splitting ratio and optical power loss.

For example, a 1×2 splitter divides one input signal into two outputs, while a 1×32 splitter distributes the input signal across 32 output ports.

As the number of output ports increases, the optical power available at each port decreases.

Splitter loss charts are commonly used when evaluating PLC and FBT fiber splitters for FTTH, GPON, EPON, and other passive optical networks.

Understanding Splitter Insertion Loss

Insertion loss is the reduction in optical power measured between a splitter’s input and an individual output port.

It is expressed in decibels (dB) and depends on the splitting ratio, splitter design, operating wavelength, and manufacturing characteristics.

For example, a 1×8 splitter divides the input power among eight outputs. Even under ideal conditions, each output receives only a fraction of the original optical power.

The actual insertion loss is generally higher than the theoretical splitting loss because practical splitters introduce additional optical losses.

Theoretical Splitting Loss

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

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

Where N is the number of output ports.

For example:

• 1×2 splitter: approximately 3.01 dB

• 1×4 splitter: approximately 6.02 dB

• 1×8 splitter: approximately 9.03 dB

• 1×16 splitter: approximately 12.04 dB

• 1×32 splitter: approximately 15.05 dB

• 1×64 splitter: approximately 18.06 dB

These values represent ideal splitting loss rather than the actual insertion loss of a manufactured splitter.

Excess Loss

Excess loss refers to additional optical power loss caused by the physical characteristics and manufacturing process of a splitter.

For an ideal equal-ratio splitter, a simplified relationship is:

Insertion Loss ≈ Ideal Splitting Loss + Additional Loss

In practical devices, insertion loss can also vary between output ports. Therefore, actual performance should be evaluated using the manufacturer’s specifications and test results.

Fiber Optic Splitter Loss Chart

The following table shows the theoretical splitting loss for common equal-ratio fiber optic splitters.

Note: These are theoretical values for ideal equal-ratio splitters, not guaranteed insertion-loss specifications. Actual insertion loss depends on the splitter design, operating wavelength, and product performance.

The table illustrates an important relationship: each doubling of the output count increases the theoretical splitting loss by approximately 3 dB.

For example, increasing the split ratio from 1×8 to 1×16 raises the ideal splitting loss from approximately 9.03 dB to 12.04 dB.

This relationship is useful when estimating optical loss during the initial design of a passive optical network.

How to Read a PLC Splitter Loss Chart

A PLC splitter loss chart helps engineers compare optical loss across different splitting ratios.

When evaluating a 1×8, 1×16, or 1×32 PLC splitter, the chart provides an initial reference for the expected power reduction at each output.

However, theoretical loss values should not be treated as the actual specifications of a particular splitter.

Important parameters to verify include:

• Split ratio: Number of output ports

• Maximum insertion loss: Highest specified loss for an output path under defined conditions

• Operating wavelength: Wavelength range over which performance is specified

• Uniformity: Difference in insertion loss among output ports

• Return loss: Optical reflection performance

For network design, use the maximum insertion loss stated in the applicable product datasheet or test report rather than relying only on theoretical values.

How Splitter Loss Affects the PON Optical Power Budget

Splitter insertion loss is an important part of the optical power budget in a passive optical network.

The total optical loss of a PON link generally includes:

• Fiber attenuation

• Connector loss

• Splice loss

• Splitter insertion loss

• Other passive component losses

A simplified optical power budget relationship is:

Available Optical Power Budget ≥ Total Link Loss

For example, when a network uses a higher splitting ratio, more output connections may be supported, but the optical power available at each output is reduced.

A 1×32 splitter has approximately 6 dB more theoretical splitting loss than a 1×8 splitter.

Therefore, increasing the splitting ratio requires careful consideration of the available optical power budget.

Network engineers should include the actual maximum insertion loss of the selected splitter when calculating the total link loss.

PLC Splitter vs. FBT Splitter Loss

PLC (Planar Lightwave Circuit) and FBT (Fused Biconical Taper) splitters use different manufacturing technologies.

Although both divide optical signals, their actual insertion-loss characteristics may differ.

For example, two 1×8 splitters have the same theoretical splitting loss if they distribute power equally. However, their specified insertion loss may differ because of device design, wavelength characteristics, and manufacturing tolerances.

When comparing PLC and FBT splitters, evaluate the actual performance specifications rather than relying only on the split ratio.

For a broader comparison of splitter technologies and configurations, see our guide to fiber optic splitter types.

How Is Fiber Splitter Insertion Loss Tested?

Insertion loss is measured by comparing the optical power entering the splitter with the power measured at an individual output port.

The difference between the reference input power and the measured output power is expressed in decibels.

Testing should use suitable optical measurement equipment, reference methods, operating wavelengths, and connector configurations.

For manufactured splitters, insertion-loss measurements can be compared with the applicable product specifications to evaluate performance.

Common Mistakes When Using a Splitter Loss Chart

1. Confusing Theoretical Loss with Actual Insertion Loss

Theoretical splitting loss describes ideal optical power distribution.

Actual insertion loss includes additional losses introduced by the splitter.

2. Using a General Chart as a Product Specification

A reference chart provides useful theoretical values but cannot replace a manufacturer’s datasheet.

Always check the specified maximum insertion loss for the selected splitter.

3. Ignoring the Operating Wavelength

Splitter performance can vary with wavelength.

Insertion-loss comparisons should be made using equivalent wavelengths and test conditions.

4. Ignoring Other Link Losses

Splitter loss is only one component of the total optical link loss.

Fiber attenuation, connector loss, splice loss, and other passive losses must also be considered when evaluating a PON optical power budget.

Conclusion

A fiber optic splitter loss chart provides a useful reference for understanding how optical loss increases with the splitting ratio.

The theoretical splitting loss increases by approximately 3 dB each time the number of equal-power output ports doubles. However, actual splitter insertion loss also depends on the device design, operating wavelength, and manufacturing characteristics.

When evaluating PLC or FBT splitters, use the manufacturer’s specified maximum insertion loss and consider the complete optical power budget of the network.

Explore our range of PLC fiber optic splitters for different splitting ratios and FTTH network applications.