Thunderbolt, originally codenamed "Light Peak," was co-developed by Apple and Intel and is considered a faster alternative to USB 3.0. The technology was originally designed to utilize optical cables as its defacto hardware standard. Unfortunately, optical cabling was abandoned for much more cost-efficient copper cabling. The substitution still provided Intel and Apple with 10Gbps of bidirectional bandwidth, however the tradeoff is that copper cabling can only reach approximately 6 meters (~19.6 feet) at its theoretical maximum and won't be able to scale beyond 10Gbps.
On the bright side, Intel executives say optical cables will be good for data transfers over longer distances of 10 meters (~32.8 feet) - possibly even "tens of meters." But according to Intel spokesperson Dave Salvatore, however, devices connected at this distance wouldn't be able to receive adequate power because impedance issues would make sending up to 10W impractical.
Nevertheless, existing Thunderbolt ports on Apple’s Mac computers will be compatible with the upcoming optical cables. Users will be able to purchase existing Thunderbolt products and switch from copper to optical cabling without any need for hardware revision changes, firmware changes, etc.
Thunderbolt optical cabling will be released in the second half of this year, but is expected to be limited to very select usage scenarios with particular needs to deploy several hundred feed of optical cabling (see: enterprise and professional contracting purposes). Analysts suggest that Intel's optical Thunderbolt cables would be expensive as well, considering that the company cited optical cabling as one of the reasons for its decision to launch the standard on copper cabling in the first place.
Intel has also stated that it is currently developing a Thunderbolt for PCI-Express 3.0 protocol, which would be able to push data significantly faster at 8GT/s (gigatransfers-per-second) compared to PCI-Express 2.0's transfer speed of 5GT/s (gigatransfers-per-second).