Alcatel-Lucent and Apollo SCS (Submarine Cable System), which sells transatlantic bandwidth to telcos and ISPs, has transmitted about 3Tbps (bits per second) across the Atlantic Ocean, the companies said in a statement.

The demonstration was conducted over a distance of 6,221 kilometers using Apollo's North cable system, which was announced in 2003 and links the US and the UK. Seventy-two channels at 40Gbps were carried over one fibre pair during the demonstration, according to Alcatel-Lucent. That's twice as fast as existing systems, the company said.

Today, most transoceanic cables use channels that can transmit up to 10Gbps. The hope among Apollo's operator customers is that the switch to 40Gbps channels will help cut costs, according to Dan Hughes, sales and marketing director at Apollo. But Apollo still isn't sure what the price difference will be between four 10G bps channels and one 40Gbps channel, Hughes said.

To upgrade from 10Gbps to 40Gbps, Apollo needs to equip its Alcatel-Lucent 1620 Light Manager submarine line terminals, which are on land, with new line cards. No changes are needed under the ocean surface. If that had been the case, the upgrade would have been commercially very difficult to justify, Hughes said.

Apollo's roll out of 40Gbps will likely start at the beginning of 2011, according to Hughes.

Just like on land, the need for more undersea capacity comes from the increasing amount of video traffic - for instance, from HD video conferencing and YouTube clips sent using the Internet, according to Hughes.

The successful demonstration was announced at the SubOptic trade show in Japan, where Alcatel-Lucent also showed a prototype of an upcoming system that will support 100Gbps per wavelength. Alcatel-Lucent isn't saying publicly when that system will start shipping.