Using a single light source, a group of researchers at the Technical University of Denmark (DTU), Chalmers University of Technology in Gothenburg, Sweden, and Fujikura Optical Technology R&D Center in Japan transmitted 1.8Pb/s of data using a method that could significantly reduce electricity usage and help reduce the climate footprint of the Internet.
The light source used in the experiment is a custom-designed optical chip that produces a spectrum of multiple colors using light from a single infrared laser, multiplying one frequency (color) of a single laser into hundreds of frequencies in a single chip.
The chip produces a frequency comb, which allows each frequency to be isolated and used to imprint data. The frequencies can be recombined and sent over optical fiber, allowing even large amounts of data to be transmitted. Experimental demonstrations have shown that a single chip can easily carry 1.8Pb/s, which might require more than 1000 lasers if the most advanced commercial equipment of our time is used.
Victor Torres Company, a professor at Chalmers University of Technology, is the head of the research team that developed and manufactured the chip. He said this particular application was not the chip's original purpose. "The fact is that certain characteristic parameters are coincidental rather than by design. However, through the efforts of my team, we are now able to reverse-engineer the process and implement microcombs for telecom target applications with high reproducibility." He said.
The researchers also created a computational model to theoretically test the fundamental potential for data transmission using the same single chip as the one used in the experiment. The calculations show great potential for scaling the solution. Professor Leif Katsuo Oxenløwe, head of the DTU Silicon Photonics Center of Excellence (SPOC) for Optical Communications, explains: "Our calculations show that with the single chip and single laser made at Chalmers University of Technology, we will be able to transmit up to 100Pb/s. The reason for this is that our solution is scalable, both in creating many frequencies, or in dividing the frequency combs into many spatial copies and then optically amplifying them and using them as parallel sources to which we can transmit data. Although the comb copies have to be amplified, we don't lose the quality of the combs, which we use for spectrally efficient data transfer."
He also believes that the solution may herald the future of power consumption on the Internet. He says, "Our solution has 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."
There is still some development work to be done before the solution can be commercialized and implemented in current communications systems," he explained, "and this is true for this as well. The more components we can integrate in the chip, the more efficient the whole transmitter will be. IE. lasers, comb chips, data modulators and any amplifier components. It will be an extremely efficient optical transmitter for data signals."
