Later on this year you'll be able to get your hands on cabling capable of carrying data at a staggering 800Gbps. But you're not going to be using these to connect your external hard drive up to your PC. Instead, these cables are headed for use in supercomputers and datacenters.
By combining up to 64 optical fibers, each capable of a transfer rate of 25Gbps, the cable is capable of a total transfer rate of 1.6Tbps. But because the MXC cable (in case you're wondering, MXC doesn't stand for anything) uses half the fibers for up and the other half for down, the transfer rate is cut to only 800Gbps.
Read more at: Intel's new 1.6Tbps optical cabling leave copper in the dust | ZDNet