Australian scientists say they have broken data communications speed records by shifting 44.2 terabits per second over 75km of glass fiber from a single optical chip.
The five-by-nine millimetre prototype gizmo is described as a micro-comb in a paper detailing its workings, published in Nature Communications on Friday. Light shone into the micro-comb is looped around a ring to produce 80 beams at various infrared wavelengths. Each beam carries a stream of data.
“The wavelengths produced from the chip are all correlated, so we can pack the individual data streams together very tightly, using almost all of the available spectrum,” Dr Bill Corcoran, first author of the study and a lecturer at Australia's Monash University, told The Register.
“This is where our 'ultradense' description comes from for the paper, it effectively shrinks down a rack of lasers into a chip to pack in as much data as possible.”
The team at Monash University, Swinburne University, and RMIT University, all Down Under, tested their chip by transmitting data over 75 kilometers of fiber optic cables to a receiver. The data here was “randomised test patterns” to stress-test the tech. The headline figure of 44.2Tbps is the raw bit rate, and adding overhead will slow it down, as the paper acknowledges:
We achieved a raw bitrate (line-rate) of 44.2 Tb/s, which translates to an achievable coded rate of 40.1 Tb/s (in B2B), dropping to 39.2 Tb/s and 39.0 Tb/s for the lab and field-trial transmission experiments, respectively.
“We used a next-generation optical modulation format with 500 gigabits-per-second per wavelength. With the 80 micro-comb wavelengths, this combined to form an optical super-channel, which added up to 40 terabits per second,” Corcoran said.
It’s not the first time researchers have experimented with micro-combs for broadband connectivity. Corcoran estimated the technology is maybe five years away from leaping from lab experiments to real-world commercial applications. Its uses in backbone links and global transit paths for the internet are obvious; it's a little much for your home broadband right now, though.
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“We’re currently getting a sneak-peek of how the infrastructure for the internet will hold up in two to three years’ time, due to the unprecedented number of people using the internet for remote work, socialising and streaming,” Corcoran added in an announcement of the breakthrough. "It’s really showing us that we need to be able to scale the capacity of our internet connections.
“And it’s not just Netflix we’re talking about here – it’s the broader scale of what we use our communication networks for. This data can be used for self-driving cars and future transportation and it can help the medicine, education, finance and e-commerce industries, as well as enable us to read with our grandchildren from kilometres away.”
But before then, boffins will have to figure out how to refine the system using modulators. “The next technological challenge is integrating the modulators – these are devices that take electrical information and put this onto light – with the micro-comb to really make this all work together on a chip-scale device,” Cocoran told El Reg.
“We've got a project that plans to pilot some of those technologies running right now, and there are other groups looking at different approaches to this. It's a bit of a race at the moment." ®