A single laser and chip can transmit all Internet traffic in under one second
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The conveyance of knowledge is increasingly becoming modern humanity’s lifeblood, and we have become increasingly proficient at it. Optical fibre communication, today, makes up the backbone of the Internet as we know it and allows Internet traffic to transit from one network node to another. While essential core electronic communications technologies approach their limits of size, speed and energy-efficiency, new technologies that offer further scaling of data transmission capacity by utilising the existing cable infrastructure with a relatively simple swap in the edge devices have become the holy grail in faster communications as these avoid the cost of having to lay further kerb-side and cabinet-based infrastructure that is always very costly. This has already happened with Dense Wave Division Multiplexing, which has sought to use the same fibre optic pipe and to send through 4 different colours of light rather than one, thereby quadrupling capacity at the relatively low cost of switching the multiplexing, demultiplexing and repeating equipment.
Now new research has discovered that a single optical frequency-comb source based on a silicon nitride ring resonator supports data capacities in the petabit-per-second regime. This is astoundingly fast and constitutes the most recent record for information bandwidth. Indeed, it is so mind-bogglingly fast that we must compare it to the entirety of Internet traffic in order to comprehend the scale of the discovery. Researchers were able to send 1.8 petabits per second with a single laser and a single optical device. Scaling this in terms of the size of the Internet, one petabit is equal to one million gigabits, and transmitting this amount of data is equivalent to transmitting twice as much as the worldwide Internet traffic taken on a per second basis.
The optical chip alone is responsible for the astounding accomplishment. It is designed as a “frequency comb” that can convert laser light into a spectrum of frequencies. Each of the equally-spaced frequencies (resembling a comb’s teeth) can carry its own data stream, which is subsequently transferred by fibre optics. This thus works on the same principle of Orthogonal Frequency-Division Multiplexing (OFDM) but scales it up to an extent that was previously not thought possible. Without this frequency division, 1,000 lasers would be required to transmit the same amount of data. Interestingly, it was not designed specifically for fiberoptic transmission, although it excels at it.
This chip produces a frequency comb with ideal characteristics for fiber-optical communications – it has high optical power and a broad bandwidth within the spectral region of interest for advanced optical communications, according to Victor Torres Company, head of the research group that developed the chip and professor at Chalmers University of Technology who claimed that “In actuality, several of the defining criteria were achieved by accident and not by purpose. With the efforts of my team, we are now able to reverse-engineer the process and produce microcombs with good reproducibility for use in telecommunications applications”.
In addition, the researchers modelled the device and demonstrated that it may eventually make the transmission 50 times faster still. The ability to transfer so much data with a single laser would dramatically lower the energy requirements of communication devices thereby cutting down on the electricity and environmental costs of telecommunications infrastructure.
“In other words, our system has the potential to replace hundreds of thousands of power-hungry and heat-generating lasers deployed in Internet hubs and data centres”, Professor Leif Katsuo Oxenlwe from the Technical University of Denmark remarked, “We have the possibility to contribute to the development of an Internet with a lower carbon footprint.”
The team, along with others across the world, is attempting to merge the laser and other components inside the chip itself in order to make it more efficient and even less energy-intensive.
The article on which this news item is based was published in Nature Photonics and may be found here.
