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Infinera and Windstream Beam 800 Gigabits Per Second Through a Single Optical Fiber

The 800G fiber optic demonstration was the first of its kind in a live network

2 min read
A conceptual illustration of high speed optical fiber
Illustration: iStockphoto

For the first time, an 800 gigabit per second connection has been made over a live fiber optic link. The connection, a joint test in June conducted by Infinera and Windstream, beamed through a fiber optic line stretching from San Diego and Phoenix. If widely implemented, 800G connections could reduce the costs of operating long-haul fiber networks.

800G should not be confused with the more commonly-known 5G cellular service. In the latter, the “G” refers to the current generation of wireless technology. In fiber optics, the “G” indicates how many gigabits per second an individual cable can carry. For most long-haul routes today, 100G is standard.

The test conducted by Infinera, an optical transmission equipment manufacturer, and Windstream, a service provider, is not the first 800G demonstration, nor is it even the first 800G over long distances. It is, however, the first demonstration over a live network, where conditions are rarely, if ever, as ideal as a laboratory.

“We purposely selected this travel route because of how typical it looks,” says Art Nichols, Windstream’s vice president of architecture and technology.

In a real-world route, amplifiers and repeaters, which boost and regenerate optical signals respectively, are not placed regularly along the route for optimal performance. Instead, they’re placed near where people actually live, work, and transmit data. This means that a setup that might deliver 800 Gbps in a lab may not necessarily work over an irregular live network.

For 800G fiber, 800 Gbps is the maximum data rate possible and usually is not sustainable over very long distances, often falling off after about 100 kilometers. The 800G test conducted by Infinera and Windstream successfully delivered the maximum data rate through a single fiber across more than 730 km. “There’s really a fundamental shift in the underlying technology that made this happen,” says Rob Shore, the senior vice president of marketing at Infinera.

Shore credits Infinera’s Nyquist subcarriers [PDF] for sustaining maximum data rates over long distances. Named for electrical engineer Harry Nyquist, the subcarriers digitally divide a single laser beam into 8 components.

“It’s the same optical signal, and we’re essentially dividing it or compartmentalizing it into separate individual data streams,” Shore says.

Infinera’s use of Nyquist subcarriers amplifies the effect of another, widely-adopted optical technique: probabilistic constellation shaping. According to Shore, the technique, originally pioneered by Nokia, is a way to “groom” individual optical signals for better performance—including traveling longer distances before suffering from attenuation. Shore says that treating each optical signal as 8 separate signals thanks to the Nyquist subcarriers essentially compounds the effects of probabilistic constellation shaping, allowing Infinera’s 800G headline data rates to travel much further than is typically possible.

What’s next for 800G after this test? “Obviously, the very first thing we need to is to actually release the product” used for the demonstration, Shore says, which he expects Infinera to do before the end of the year. 800G fiber could come to play an important part in network backhaul, especially as 5G networks come on-line around the world. All that wireless data will have to travel through the wired infrastructure somehow, and 800G fiber could ensure there will be bandwidth to spare.

The Conversation (0)

Metamaterials Could Solve One of 6G’s Big Problems

There’s plenty of bandwidth available if we use reconfigurable intelligent surfaces

12 min read
An illustration depicting cellphone users at street level in a city, with wireless signals reaching them via reflecting surfaces.

Ground level in a typical urban canyon, shielded by tall buildings, will be inaccessible to some 6G frequencies. Deft placement of reconfigurable intelligent surfaces [yellow] will enable the signals to pervade these areas.

Chris Philpot

For all the tumultuous revolution in wireless technology over the past several decades, there have been a couple of constants. One is the overcrowding of radio bands, and the other is the move to escape that congestion by exploiting higher and higher frequencies. And today, as engineers roll out 5G and plan for 6G wireless, they find themselves at a crossroads: After years of designing superefficient transmitters and receivers, and of compensating for the signal losses at the end points of a radio channel, they’re beginning to realize that they are approaching the practical limits of transmitter and receiver efficiency. From now on, to get high performance as we go to higher frequencies, we will need to engineer the wireless channel itself. But how can we possibly engineer and control a wireless environment, which is determined by a host of factors, many of them random and therefore unpredictable?

Perhaps the most promising solution, right now, is to use reconfigurable intelligent surfaces. These are planar structures typically ranging in size from about 100 square centimeters to about 5 square meters or more, depending on the frequency and other factors. These surfaces use advanced substances called metamaterials to reflect and refract electromagnetic waves. Thin two-dimensional metamaterials, known as metasurfaces, can be designed to sense the local electromagnetic environment and tune the wave’s key properties, such as its amplitude, phase, and polarization, as the wave is reflected or refracted by the surface. So as the waves fall on such a surface, it can alter the incident waves’ direction so as to strengthen the channel. In fact, these metasurfaces can be programmed to make these changes dynamically, reconfiguring the signal in real time in response to changes in the wireless channel. Think of reconfigurable intelligent surfaces as the next evolution of the repeater concept.

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