New record set for data-transfer speeds.


Researchers at IBM have set a new record for data transmission over a multimode optical fiber, a type of cable that is typically used to connect nearby computers within a single building or on a campus. The achievement demonstrated that the standard, existing technology for sending data over short distances should be able to meet the growing needs of servers, data centers and supercomputers through the end of this decade, the researchers said. Sending data at a rate of 64 gigabits per second (Gb/s) over a cable 57 meters long using a type of laser called a vertical-cavity surface-emitting laser (VCSEL), the researchers achieved a rate that was about 14 percent faster than the previous record and about 2.5 times faster than the capabilities of today’s typical commercial technology.

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To send the data, the researchers used standard non-return-to-zero (NRZ) modulation. “Others have thought that this modulation wouldn’t allow for transfer rates much faster than 32 Gb/s,” said researcher Dan Kuchta of the IBM T.J. Watson Research Center in New York. Many researchers thought that achieving higher transmission rates would require turning to more complex types of modulation, such as pulse-amplitude modulation-4 (PAM-4).

“What we’re showing is that that’s not the case at all,” Kuchta said. Because he and his colleagues achieved fast speeds even with NRZ modulation, he added, “this technology has at least one or two more generations of product life in it.”

Kuchta will describe these results at the 2014 OFC Conference and Exposition being held March 9-13 in San Francisco.

To achieve such high speeds, the researchers used the VCSEL lasers developed at Chalmers University of Technology in Sweden and custom silicon-germanium chips developed at IBM Research. “The receiver chip is a unique design that simultaneously achieves speeds and sensitivities well beyond today’s commercial offerings,” Kuchta explained. “The driver chip incorporates transmit equalization, which widens the bandwidth of the optical link. While this method has been widely used in electrical communication, it hasn’t yet caught on in optical communication,” he said.

“Researchers typically rely on a rule of thumb that says the usable data-transfer rate is about 1.7 times the bandwidth,” Kuchta explained. “That means that with the VCSEL laser, which has a bandwidth of about 26 GHz, the rate would be only about 44 Gb/s.”

“What we’re doing with equalization is we’re breaking the historical rule of thumb,” Kuchta said.

The fast speeds only worked for a distance of 57 meters, so this technology isn’t designed for sending data across continents. Instead, it’s most suitable for transmitting data within a building, he said. About 80 percent of the cables at and most, if not all, of the cables used for typical supercomputers are less than 50 meters long.

Scientists break world record for data transfer speeds.


Researchers are claiming a new world record for data transfers over long distances.

Data was moved back and forth at a combined rate of 186Gbps (gigabits per second), fast enough to transfer two million gigabytes of data or 100,000 full Blu-ray discs in one day.

It could pave the way for networks with standard speeds of 100Gbps.

That would speed up the sharing of scientific research, such as that at the Large Hadron Collider.

The tests involved sending data between the University of Victoria in Victoria, British Columbia, and the Washington State Convention Centre in Seattle.

The team achieved two-way data rates of 186Gbps, breaking their previous record of 119Gbps set in 2009. The data’s fastest speed in a single direction was 98Gbps.

By contrast current fibre optic networks have a top speed of about 1Gbps.

The distances spanned nearly 131 miles (212km) and relied on the latest optical equipment, highly tuned servers and ran over a 100Gbps circuit, set up by CANARIE, Canada’s Advanced Research and Innovation Network.

In an even larger demonstration, researchers transferred massive amounts of data between a booth at the SuperComputing 2011 conference in Seattle and other locations within the US, Brazil and Korea.

The experiments brought together physicists, computer scientists and network engineers from a range of institutions, including the California Institute of Technology, the University of Victoria, the University of Michigan, the European Centre for Nuclear Research (Cern) and Florida International University.

“Our group and its partners are showing how massive amounts of data will be handled and transported in the future,” said Harvey Newman, a professor of physics who headed up the physicist team.

According to the researchers the achievement will help establish new ways to transport the increasingly large amounts of data that currently travel via optical fibre networks across continents and under oceans.

“Having these tools in our hands allows us to engage in realisable visions others do not have. We can see a clear path to a future other cannot yet imagine with any confidence,” said Prof Newman.

Fast data transfers are particularly crucial for sharing the work of big scientific projects, such as work at the Large Hadron Collider (LHC).

The LHC has made the headlines this week as scientists announced that they could have seen first glimpses of the elusive Higgs boson particle, believed to be responsible for giving everything in the universe its mass.

At Cern the group of scientists behind the particle accelerator have so far processed, distributed and analysed more than 100 petabytes of data – over four million Blu-ray discs – in their search for a better understanding of the nature of matter, space and time.

Data volumes are expected to rise as the team cranks up their efforts and it is crucial to be able to share the data with researchers around the world.

Enabling scientists anywhere in the world to work on the LHC data is a key objective of the project as it seeks to solve some of the biggest mysteries of the universe.

“One can think of these 100Gbps links as a huge highway for our data. But we obviously don’t ship data just to take it on a cruise: we want to get it from A to B because B will do the number crunching. And that in turn means we now have a huge bandwidth of data to crunch on,” said Axel Naumann, one of the LHC scientists.

“The 100Gbps demonstration… is pushing the limits of network technology by showing that it is possible to transfer petascale particle physics data in a matter of hours to anywhere around the world,” said Randall Sobie, a research scientist at the Institute of Particle Physics in Canada and a team member.

The push for higher data rates in light-based telecommunications technologies has seen a number of significant leaps in recent years.

In May, researchers set a new record for the rate of data transfer using a single laser: 26 terabits per second.

At those speeds, the contents of nearly 1,000 high-definition DVDs could be sent down an optical fibre in a second.

Source: science.