BT Runs an 800Gbps Channel On Old Fiber

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."

Comments

That's great and all

[Rosco P. Coltrane]

But when will they upgrade my 4Mbps down / 256Kbps up DSL connection that I pay through the nose per month for? Cuz really, I keep reading about those marvelous link speeds but in the past 10 years, I haven't seen much of that reach the average Joe Blow internet user like me...

Re:That's great and all

[AmiMoJo]

It's the last mile problem, and they haven't even started working on it really. New estates are being built with only FTTC and ADSL available instead of just taking the opportunity to run fibre right into each home.

BT always does the absolute minimum possible to remain slightly competitive. That's all we can ever expect.

Re:That's great and all

[FireFury03]

Fibre providers have an ONU (optical network unit) supplied by the mains power on the property. Unless there's some kind of requirement for power-free phones I don't know about there really is no reason to run expensive copper wires.

Fairly sure there's a legal requirement for the telco to keep the phones working during a power outage. Certainly do-able with fibre, but would require a UPS and regular battery servicing - probably cheaper just to run copper.

Re:That's great and all

[johnw]

Having said all that for reasons I don't understand Openreach want separate ducting for copper and fibre but that is just plain crazy if you ask me.

Obviously they are worried about cross-channel interference. That or the danger of high voltages on the fibre connections.

GBps != Gbps

[luminate]

Might want to change the title...

Re:GBps != Gbps

[Impy the Impiuos Imp]

Wait, shouldn't it be UKbps?

Glass is glass..

[Annorax]

No news here people. The fact that existing fiber optic cable can be reused with new terminating equipment to increase transmission speed is not anything new.

MCI was doing this throughout the 1990s.

The inherent properties of the fiber optic cable have always meant that their potential "max speed" was much higher than the current terminating equipment of the time.

This is as interesting as someone saying "Hey, I bought a new sports car and drove it faster on this old road today than I did on my motor scooter yesterday!"

Re:Glass is glass..

[Shatrat]

It's heartbreaking to see how little the average slashdotter actually knows about technology when they start talking about my field.

First, optical amplifiers are not 're-encoders' which isn't a real term anyway, the closest thing to what you mean is a 'transponder' and those are only used at end-points. The two types of optical amplifiers are Erbium Doped Fiber Amplifiers and Raman effect amplifiers. They do not receive and retransmit, they literally add photons of the exact same wavelength and polarity as the original signal, with no interruption.

This article is ultimately about how the new coherent DSP enabled 100G and beyond fiber optic gear is actually much more tolerant of noise, chromatic dispersion, and polarization mode dispersion than the previous 10G on-off keyed gear. That allows carriers to go back and use fiber types that we used years ago that are obsolete, such as Zero Dispersion Shifted fiber.

Yes, technology always offers improvements, but this is not an incremental improvement. This is a huge leap forward.