Successful 400 Gbps trials open the door for faster fiber

Speeds of 400 gigabits per second, or 50 gigabytes of data sent in one second over existing infrastructure, promises higher new commercial fiber speeds.

400 Gbps internet speeds fiber

400G card

Credit: Alcatel-Lucent

We've been hearing about speed trials over fiber for years. In 2009, researchers in Denmark were the first to beat the one-terabit mark. For comparison, today's commercial fiber usually runs at 100 gigabits per second.

This year's real-world tests, by switch-maker Alcatel-Lucent over existing long-distance fiber, have obtained 400 gigabits per second, or 50 gigabytes in one second.

That's especially good because it's real-world and four times better than the current, normally available pipes.

Bits are used to measure rate of transfer, and bytes to measure capacity, by the way.


Some background: In mid-2014, that same Danish group at the Technical University of Denmark obtained 5.4 terabytes in one second (5,400 gigabytes in one second), beating out a 2011 German transmission of 3.15 terabytes in one second—the Library of Congress in three seconds, ExtremeTech reported at the time.

Later that year, Dutch scientists achieved 32 terabytes in one second. That's 32,000 gigabytes in one second.

Even higher speeds have been obtained, but that's been with multiple lasers over multiple fibers.

Commercial world

But Alcatel-Lucent's recent test in Spain, carried out with Mobile Network Operator (MNO) Vodafone obtaining 400 gigabits per second, using existing fiber over 400 km, is notable because it's over distance with existing cables. There was no re-engineering of the optical link.

Earlier this month, Light Reading reported that Alcatel Lucent said it had carried out another trial, this time with T-Mobile Czech Republic over 320 km between Prague and Hradec Králové. Similar speeds were obtained.

Faster is better

Commercial links don't match those in he lab, which is why these non-record-making speeds tests are interesting.

It's also one reason why an on-demand movie download doesn't happen instantaneously, even with the latest-available gigabit fiber.

Theoretically, these successful Alcatel-Lucent tests mean that networks ultimately will be able to transmit a 4-gigabyte, two-hour movie four times faster than before, and send 12 movies instead of three in the same one-second time-frame—in the same cable.


Alcatel-Lucent is obtaining the speed increases with new switches.

The technology, called 400G Clear Channel Networking, uses new gear with existing optical fiber. New elements include a one port “400G IP line card for IP networks” that “will allow data transmission between existing Alcatel-Lucent IP routers at speeds of 400 gigabits-per-second (400G) line rate over hundreds of kilometers,” the company says.

Its big advantage is that it avoids the need to aggregate the traffic over multiple 100-gigabit links, says the company.


The T-Mobile test used Alactel-Lucent''s 1830 Photonic Service Switch and 400G Photonic Service Engine over Dense Wavelength Division Multiplexing (DWDM). DWDM is a way of splitting signals in a fiber cable. The Vodafone test also used the 1830 Photonic platform.

Despite these tests obviously being for MNO-backhaul purposes, it does mean that it's likely that we will soon see additional capacity on existing networks.

Plus, the added bonus is that in doing so, there should be no disruption of existing traffic. Maybe one-day on-demand movies will show up at home faster too.

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