Looking at fiber optic image conduits, I found that they have a packing fraction (the ratio of the fiber core's area to the total area) of 100% (source here). 

In other words, they consist only of fiber core, no cladding.

But without cladding, wouldn't the light travel between the individual fibers, messing up the output image?

Or is the cladding so extremely thin that this is simply a result of rounding up to 100%?


Question: Does "surfeit" have an adjectival counterpart?
Answer: The OED attests (what it calls) the participial adjective surfeited, meaning:


  Fed or filled to excess; oppressed or disordered by or as by over-feeding.


The first citation is from Shakespeare, and two of the later ones are:


  
  1842 Manning Serm. (1848) I. 22 — Take a watchful, self-denying man..and compare him with the heavy, surfeited man. 
  1886 H. F. Lester Under Two Fig Trees 182 — And then divide the morsel among these already surfeited gluttons.
  


The now rare word surfeiting is not an adjective, but a verbal noun (or “gerund”) with the same sense as surfeit itself.  For example:


  
  1821 Lamb Elia Ser. i. Grace before Meat, — Gluttony and surfeiting are no proper occasions of thanksgiving.