Loss of a 1-to-10 optical splitter

A 1×10 optical splitter typically introduces an insertion loss of around 10.5–11 dB per output port, including splitting and excess loss.

Understanding Insertion Loss

Insertion loss is the reduction in optical power from the input to each output port of a splitter. It includes:

• Splitting loss: The theoretical loss due to dividing the input power among multiple outputs. For a 1×N splitter, the ideal splitting loss is calculated as 10·log₁₀(N) dB. For a 1×10 splitter, this gives approximately 10 dB.
• Excess loss: Additional loss caused by imperfections in the splitter, such as fusion splices, core misalignment, or manufacturing tolerances. Typical excess loss ranges from 0.5 to 2 dB depending on the splitter type and quality . Thus, the total insertion loss for a 1×10 splitter is roughly 10–11 dB per port in practical scenarios .

Splitter Types and Loss Variation

• PLC (Planar Lightwave Circuit) splitters: Offer more uniform loss across ports, with excess loss typically between 0.5–2 dB.
• FBT (Fused Biconical Taper) splitters: At higher split ratios like 1×10, they may exhibit slightly higher insertion loss and greater variation between ports .

Practical Considerations

• Uniformity loss: Even high-quality splitters have slight differences in output power between ports. PLC splitters may vary ±0.8 dB, while FBT splitters can vary ±1.5 dB .
• Link budget: Total optical loss also includes fiber attenuation (e.g., 0.35 dB/km at 1310 nm), connector loss (~0.3 dB per pair), and splice loss (~0.1 dB per splice). A safety margin of 3 dB is often added for reliable operation .
• Example: If a transmitter outputs +3 dBm, after a 1×10 splitter with ~10.5 dB insertion loss, each port would receive approximately -7.5 dBm. Additional fiber and connector losses must be subtracted to ensure the receiver operates above its minimum sensitivity .

Summary

For a 1×10 optical splitter:

• Ideal splitting loss: ~10 dB
• Typical excess loss: 0.5–1 dB
• Total insertion loss per port: ~10.5–11 dB
• Variation between ports: ±0.8 dB (PLC) or ±1.5 dB (FBT) Understanding these values is crucial for designing fiber networks, ensuring sufficient signal strength at each output, and maintaining reliable communication in PON or FTTH systems .