EMT Grounding requirements
You don't need to ground a hamster run, either.

Suppose you had a hamster habitat.  And instead of fiber optic, you were using this EMT to extend the hamster habitat to an outdoor maze.  Would this habitat run require grounding *solely due to using EMT as a building material?  Of course not.  That would be silly. 

Well, as far as NEC is concerned, fiber-optic cable that has no DC wires running it counts the same as a hamster.  It simply does not count for anything at all, and is completely out of its jurisdiction. 

The only time fiber-optic cable is in NEC's jurisdiction is when you intermix it in a conduit with electrical wires.  But even then, they consider it disregardable if there is nothing metallic in it.