BT Test of Super-Channel a Great Success

May 24, 2013

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British Telecom (BT) recently made a major breakthrough in data communications with the successful test of their 800 Gbps “super-channel” running between Ipswich and London. The successful test was demonstrated by the company's ability to send the equivalent of seven high definition DVDs across the channel in just one second. The data was sent between BT Tower and the company's research centre at Adastral Park. To the casual observer, the announcement of the company's success may mean nothing more than the hope of faster streaming data in the near future. However, for those active in the industry, it is a monumental breakthrough given what was previously thought to be the limitations of optical fibre networks. As a case in point, BT purposely made the test as difficult as possible by using a fibre network previously believed to be incapable of carrying even 10 Gbps. The fibre’s high polarisation mode dispersion presents a special challenge in dispersing different polarisations of light. Nevertheless, BT used a new technique known as dense wave division multiplex (DWDM) to send 100, 200, and 400 Gbps signals over the fibre in addition to the 800 Gbps super-channel. The technology works around poor PMD performance by sending data using different light wavelengths all in the same stream. The different wavelengths can be combined into a single unified stream without any reduction in speed or data loss. The technology has the potential to completely revolutionize long-distance data communications. Keep in mind the long-distance angle is important here. The whole idea behind optical fibre is to increase data communications performance over long distances in order to facilitate higher capacity global data transfers. The BT test has proven it can be done, at least in concept. Now they need to scale it to the real world. From an economic standpoint, the test also goes a long way in proving BT's current fibre optic network will not require drastic overhauling in order to be ready for the high-speed future of data communications. Fibre cables now in place will be able to handle the new signal with high-tech transceivers at each end. For this test, BT used WaveLogic 3 transceivers from Ciena. Just for the record, they performed admirably.

Gradual Adoption Is the Plan

BT also revealed that their tests proved they could send streams of different speeds over the same fibre simultaneously, without any loss. The test verified what BT has been hoping for; a network that would provide for gradual adoption as the company rolls out its new technology. There will be no need to use extra fibres or drastically change current networks. The gradual adoption approach will save both BT and its customers significant amounts of money while also reducing the combined carbon footprint. The only question now is how long will it be before BT begins a large-scale rollout. More tests undoubtedly need to be done before that happens. However, make no mistake, the super-channel is here – and not a moment too soon.