A 1×8 optical splitter typically has a theoretical split loss of about 9 dB, with total insertion loss per port ranging from 10 to 12 dB depending on excess loss and network components.

Theoretical Split Loss

For a 1×8 splitter, the ideal loss is calculated using the formula: Loss (dB) = 10 × log₁₀(N) where N is the number of output ports. For 8 outputs: 10 × log₁₀(8) ≈ 9.03 dB This represents the power division assuming perfect splitting with no imperfections, meaning each port receives 1/8th of the input power .

Excess Loss

In practice, splitters have excess loss due to internal imperfections such as core misalignment, waveguide mismatch, and packaging. Typical PLC splitters have excess loss between 0.5–2 dB, while FBT splitters may have slightly higher losses at higher split ratios . For example, if a 1×8 PLC splitter has 0.8 dB excess loss, the total insertion loss per port becomes: Total Loss = Theoretical Loss + Excess Loss = 9.03 + 0.8 ≈ 9.83 dB

Practical Field Loss

When designing a network, additional losses from connectors, splices, and engineering margin must be included. For instance, a typical scenario might include:

• 2 connectors at 0.3 dB each → 0.6 dB
• 4 fusion splices at 0.1 dB each → 0.4 dB
• Engineering margin → 2 dB Adding these to the previous total: Total branch loss = 9.03 + 0.8 + 0.6 + 0.4 + 2 ≈ 12.83 dB This means each output port would receive approximately 12.8 dB less power than the input, which is crucial for ensuring the optical receivers operate within their sensitivity range .

Summary Table for 1×8 Splitter

Key Considerations

• Always refer to the splitter datasheet for exact excess loss values.
• Losses accumulate in cascaded splitters or long fiber runs.
• Ensure the received power at each ONT or optical receiver is above its minimum sensitivity to avoid errors or dropouts . By accounting for theoretical, excess, and practical losses, network designers can accurately plan the optical power budget for each port of a 1×8 splitter.