The theoretical insertion loss of a 1×116 optical splitter is approximately 20.64 dB, with additional excess loss depending on the splitter type and quality.

Theoretical Split Loss

For a passive 1×N optical splitter, the ideal insertion loss is calculated using the formula: L_split = 10 × log₁₀(N) For 116 outputs: L_split = 10 × log₁₀(116) ≈ 20.64 dB This represents the loss assuming perfect splitting with no internal imperfections .

Excess Loss

In real-world splitters, there is always excess loss caused by factors such as:

• Internal waveguide mismatches
• Fusion splices and core misalignment
• Coupler imperfections inside the splitter package Typical PLC splitters have excess loss ranging from 0.5 to 2.0 dB, while FBT splitters may have slightly higher losses at large split ratios . The total insertion loss is therefore: L_total = L_split + L_excess For example, if the excess loss is 1 dB: L_total ≈ 20.64 + 1 = 21.64 dB

Additional Losses

When planning a fiber link, you should also account for:

• Connector losses: typically 0.2–0.5 dB per connector
• Fusion splice losses: typically 0.05–0.15 dB per splice
• Engineering margin: 1–2 dB to cover aging, dirt, temperature variations, and measurement tolerances The total branch loss for a 1×116 splitter can therefore exceed 22–23 dB depending on the number of connectors, splices, and margin included.

Practical Implications

• Each output port receives only a fraction of the original optical power. For a 0 dBm input, a 1×116 splitter with 21.64 dB total loss would deliver approximately -21.64 dBm per port.
• Ensure that the receiver sensitivity of the ONTs or optical devices is sufficient to operate reliably at this reduced power.
• Large split ratios like 1×116 are uncommon in typical PON deployments; careful planning is required to maintain adequate signal strength at all outputs . By applying these calculations, network engineers can estimate the received power, design the link budget, and ensure reliable operation of high-split-ratio fiber networks.