While currently-shipping Thunderbolt cables and peripherals are still running over copper, Macworld reports that Intel has confirmed that current Thunderbolt ports in Apple's latest Macs will support data transfer over optical cables.
Back when it was known as Light Peak, Thunderbolt was originally supposed to be based on fiber optic tech, which would theoretically have allowed superior data transfer over much longer cable lengths than possible with copper. Current copper-based Thunderbolt cables can transfer data over a length of about three meters, but optical cables will be able to move data over cable lengths of "tens of meters" according to Intel. Optical cables should also allow for faster data transfers, but after citing the probable expense and stating that current Thunderbolt speeds are likely fast enough for most users, Intel is not likely to implement that feature for now.
Optically-based Thunderbolt cables should be debuting in 2012, and existing Macs' Thunderbolt ports will be fully compatible with them. Meanwhile, both Acer and Asustek are planning to introduce Windows-running PCs featuring Thunderbolt ports next year, so hopefully that means Thunderbolt won't be an also-ran connection standard the way FireWire turned out to be.