Why are optical cables jitter prone?

Forgot to mention that Robert Stein from The Cable Company told me Audio One does not use any special wire or components, but they assemble their optical cables to "very high tolerances", and evidently it makes a difference in sound quality. I guess that means very accurate and careful assembly. Maybe that has something to do with reducing jitter. I am not as informed as some of the more technically inclined here, and perhaps someone can shed a bit of light on the subject (pun intended).

Normally in a manufacturing sense it is harder and more expensive to make something with a tight tolerance. Not sure if he just stated himself wrong, but having a "high tolerance" means having a loose fit. I would expect optical cable dimensions to be critical, and thus need to be as exact as possible. Can anyone else fill in the blanks here?

Argent, I am sure you are correct, and that 'tight tolerance" was intended.