Once the reference has been selected, the problem of how to route the signal through a facility can be daunting. The standard 50-ohm coaxial cable is the most likely used but when it comes to great distances—miles or very hostile electromagnetic environments other solutions might be required. One strong candidate is fiber optic. It solves the electromagnetic capability problem and distance handily. It allows a large dispersed facility to all be on the same reference source- minimizing the investment in the primary reference and at the same time assuring timing synchronization.

The one performance area that suffers in most fiber optic links is phase noise. Most fiber optic links achieve -130dBc/Hz @1 khz. For demanding applications, the Novus LN fiber optic link aproaches -150 dBc/Hz @ 1 khz.