Downloading 230 million photos per second A world record for data transfer using only a single chip
A team of scientists at the Technical University of Denmark, Chalmers University of Technology, has achieved 1.84 trillion bits per second (Pbit) of data transmission using only a single laser and a single optical chip; this amount of data is about twice the amount of the entire Internet traffic and is equivalent to downloading 230 million photos per second: today, the average global Internet bandwidth is estimated to be about 1 Pbit/s.
The research results were published on October 20 in the journal Nature Photonics under the title "Pbit per second data transfer using a chip-scale microcomb ring resonator source" [1].
01Fiber optic communications, the backbone of the Internet, urgently needs to expand data transmission capacity
Fiber optic communications are the backbone of the Internet. As the size, speed and energy efficiency of the basic core technology approaches its limits, new technologies that can further expand data transmission capacity are needed.
To put it another way, 1.8 Pbit is equivalent to twice the amount of global Internet traffic. To achieve the same speed using the most advanced commercial equipment of our time would require more than 1,000 lasers.
The foundation of this success is the light source, a specially designed optical chip that can use light from a single infrared laser to create a rainbow of color spectra or frequencies. Each color has the ability to isolate and imprint data, which can then be recombined and sent through an optical fiber to transmit the data.
A key factor in the research and development of such chips is the so-called "Q factor (quality factor)," which is a physical measure of light loss - the higher the Q factor, the lower the loss. "Since 2019, we are one of the few teams in the world that can manufacture integrated microresonators with optical qualities in excess of 10 million." Victor Torres Company, head of the research team that developed and fabricated the chip, said [2]. Interestingly, the chip was not optimized for this specific application.
"However, through the team's efforts, we are now able to reverse engineer the process and achieve a highly reproducible microcomb in a telecom target application." Victor Torres Company said, "We are now understanding the properties of these newer, more reproducible microcombs based on what we call 'photonic molecules,' as we believe they will make possible the vision of reaching speeds per second in the future. "
02Data transfer speed of 1.84 Pbit/s, 8251 times more bandwidth
Photonic chip technology holds great promise for optical data transmission: because both the processor and the transmission medium work together with light waves. Scientists briefly explain how Danish scientists led by Asbjørn Arvad Jørgensen managed to provide such bandwidth with the resources at hand.
Communication system model. Source: Technical University of Denmark
First, the data stream used in the experiment was divided into 37 lines, each of which was sent along a different ray of light in the cable. each of the 37 data lines was divided into 223 data blocks, corresponding to regions of the spectrum. This allows the creation of a "frequency comb" in which the data is transmitted simultaneously in different colors without interfering with other streams. In other words, a "massively parallel spatial and wavelength multiplexed data transmission" system is created. Of course, this splitting and re-splitting significantly increases the potential data throughput supported by the fiber optic cable.
Testing and verifying the 1.84 Pbit/s bandwidth was not easy: no computer could send or receive, let alone store, such a large amount of data. The research team used virtual data on each channel to verify what the full bandwidth capacity was. Each channel was tested individually to ensure that the received data matched the transmitted data.
In effect, the photonic chip splits the single laser into many frequencies and requires some processing to encode the optical data for each of the 37 data fiber streams. According to Jørgensen, a compact, fully functional optical processing device should be able to be built to about the size of a matchbox - similar in size to the monochrome laser transmission devices currently used in the telecommunications industry.
Achieved data transfer rate (red triangle) vs. theoretical throughput. Source: Technical University of Denmark
Eventually, the experiment will be able to maintain the same fiber optic cable infrastructure and replace the matchbox-sized optical data encoder/decoder with a similarly sized photonic chip-powered device, potentially increasing the data bandwidth by an effective factor of 8251. The researchers say [3] that their work shows enough potential to inspire "a shift in the design of future communication systems.
03Promising to transform future communication systems with data transfer speeds of up to 100 Pbit/s
In addition, the researchers created a computational model to theoretically test the fundamental potential of using the same single chip as the experimental chip for data transmission. The researchers claim that a single chip-level light source could eventually support 100 Pbit/s in a massively parallel spatial and wavelength multiplexing data transmission system.
"Our calculations show that with the help of a single chip and a single laser made at Chalmers University of Technology, we will be able to transmit data up to 100 Pbit/s," says Prof. Leif Katsuo Oxenløwe [4]: "The reason for this is that our solution is scalable: both in terms of creating many frequencies and in terms of dividing the frequency combs into many spatial copies and then optically amplifying them and using them as parallel sources from which we can transmit data. In other words, our solution offers the potential to replace hundreds of thousands of lasers located in Internet hubs and data centers, all of which consume power and generate heat - we have the opportunity to contribute to the realization of an Internet with a reduced climate footprint."
These new findings could mark a shift in the design of future communications systems: it is aimed at device efficient transmitters and receivers.
"There is work being done all over the world to integrate laser sources into optical chips, and we are working on it. The more components we can integrate in the chip, the more efficient the whole transmitter will be, i.e., the laser, the comb creation chip, the data modulator and any amplifier element; it will be an extremely efficient optical transmitter of data signals." Leif Katsuo Oxenløwe said [5].
Reference links：
[1]https://www.nature.com/articles/s41566-022-01082-z
[2]https://www.chalmers.se/en/departments/mc2/news/Pages/Chip-from-Chalmers-enables-data-transmission-world-record-.aspx
[3]https://www.tomshardware.com/news/record-184-petabit-per-second-data-transfers-achieved-using-photonic-chip-and-fiber-optic-cable
[4]https://www.inceptivemind.com/researchers-set-world-record-transmitting-1-8-pbit-s/27972/
[5]https://phys.org/news/2022-10-transmission-laser-optical-chip.html
