we know fiber optic cables (they reach speeds that are fixed to 1-3 Gbps or as high as 10 Gbps in some cases) are being used in a few places and the number is growing but already intel are working on a new cable.
it is "silicon photonics"" that uses multiple silicon lasers that run as fast as 1Tbps, but its only experimental so far.

sorry if this is in the wrong place did not know where to put it