Energy audit of a side-glowing fiber model

Challenge

Predict how much light leaks from the side of a thin scattering fiber about 100 mm long, and where that light goes.

Approach

Two independent detector models, an energy-balance check, and a ray-limit sweep were used to see whether the ray trace kept the light it launched.

Result

Default ray-trace limits silently lost about 6% of the light launched into the fiber. Raising them cut unaccounted light to about 1% and raised the predicted side emission by about 40%.

Key figures

• ~6%

  of launched light lost under default ray-trace limits

• ~1%

  unaccounted light after the ray limits were raised

• ~40%

  predicted side emission after the ray limits were raised