FTTH DESIGN · 16 SEPTEMBER 2026

1:32 or 1:64 for an apartment or villa FTTH network?

A split ratio tells you how many branches one optical input can feed. It does not tell you whether the most distant flat or villa will receive enough optical power. That decision begins with a path-by-path loss budget.

Map the actual routes before choosing a ratio

For an apartment tower, trace the route from the OLT through the feeder, splitter, riser, floor distribution and drop to each ONT. For a villa layout, include the outside plant path, distribution points and the longest drop. Record both the longest and shortest OLT-to-ONT paths; the final design has to work across the network, not only at an average address.

Mark every connector, splice and splitter on the drawing. A distributed split architecture can be easier to route at a particular site, but each optical component on the path still belongs in the calculation.

Build the loss budget from selected components

For a first pass, add the selected splitter module’s specified insertion loss, fiber attenuation at the relevant wavelength, connector and splice losses, and an engineering allowance. Compare the total with the optical class and receiver limits of the exact OLT and ONT pair. The ITU-T G.984.2 GPON physical-layer specification provides the standards framework; equipment datasheets establish what your chosen hardware supports.

Compare the two options on a worksheet

• Route: feeder distance, distribution distance and the longest and shortest customer drops.
• Components: selected 1×32 or 1×64 splitter model, connector count and splice count for each path.
• Optics: actual OLT/ONT class and loss limits for the technology being deployed.
• Capacity: planned active connections, spare branches, PON port availability and the operator’s shared bandwidth requirement.
• Margin: allowance for field variation, future changes and maintenance.

Run the worksheet for both architectures. A 1:64 design serves more potential branches per PON port, but it may leave less optical headroom. A 1:32 or staged split can make sense when routes are longer or the design needs more margin. Neither choice is automatically correct for all apartments or all villas.

Keep GPON and XGS-PON calculations separate

If a property may later support XGS-PON, document that requirement early. The ITU-T G.9807.1 XGS-PON recommendation is a separate standard. Check its wavelength, coexistence and equipment specifications rather than copying a GPON loss budget into a future upgrade plan.

Our FTTH estimator is useful for exploring a preliminary layout, with its generic assumptions displayed beside the results. A final bill of materials and optical budget should use your site survey and selected manufacturers’ specifications.