Fiber Optic Cable & Photonic Interconnects worked example

Fiber Draw Yield at 69% target fiber draw yield: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop target fiber draw yield to 69%, then walk the calculation through step by step. Calculate fiber draw yield from accepted drawn fiber length versus started draw length and compare it with the production target.

The inputs for this scenario

  • Accepted drawn fiber length: 238,000 m, km, or ft (held at the documented default)
  • Started draw length: 250,000 m, km, or ft (held at the documented default)
  • Target fiber draw yield: 69 % (the input this scenario stresses; the baseline uses 96)

Working through the calculation

  • The calculation starts from the formula this tool documents: Fiber draw yield = accepted drawn fiber length ÷ started draw length.
  • Fiber draw yield works out to 95.2 % at these inputs, and this is the headline figure for the scenario.
  • Gap to draw-yield target works out to -26.2 points at these inputs.
  • Accepted drawn fiber length works out to 238,000 m, km, or ft at these inputs.
  • Started draw length works out to 250,000 m, km, or ft at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where target fiber draw yield sits at 96% and the headline result is 95.2 %, this scenario lands almost exactly on the baseline at 95.2 %.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to target fiber draw yield, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It is a length-based ratio only — it does not weight by attenuation grade, mode field diameter, or the cost difference between a break early versus late in the draw.

Results at a glance

  • Fiber draw yield: 95.2 % (headline result)
  • Gap to draw-yield target: -26.2 points
  • Accepted drawn fiber length: 238,000 m, km, or ft
  • Started draw length: 250,000 m, km, or ft

Run it with your numbers

  • To rerun this with your own numbers, open the live Fiber Draw Yield calculator, set target fiber draw yield to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.