judgecorp writes "BT has demonstrated an 800Gbps 'superchannel' on a 410km fiber in its core network, which was not able to carry 10Gbps channels using older technology. The superchannel is an advanced dense wave division multiplexing (DWDM) technique, created by combining multiple coherent optical signals into one channel, which had previously been shown in laboratory tests. BT ran the test on a fiber with optical characteristics (high polarization mode dispersion) that made it unsuitable for 10GBps using current techniques. That's a good result for BT, because it means its existing core fiber network can be upgraded to handle more data. It's also a good customer story for Ciena, which makes the optical switches used in the test."