This computer chip breaks records… Thanks to a technology that uses light spectra, it has proven capable of transmitting 1.84 petabits of data per second via a fiber optic cable, the equivalent (in quantity of data) of global Internet traffic in one second.
To give an idea of the immense amount of data transmitted via this method, a few comparisons are possible. For example, 1.84 petabits of data is enough bandwidth to download 230 million photographs during that time, but also more traffic than can be picked up per second on the entire Internet.
Those responsible for this technical feat are a certain Asbjørn Arvad Jørgensen, a researcher at the Technical University of Denmark in Copenhagen, and his colleagues. They used a photonic chip for this. This technology consists of placing optical components on computer chips. The idea is to divide a data stream into several thousand separate channels. These different channels were all transmitted at the same time, but well separated, over a distance of several kilometres. It is this separation that allows more data to be transported at one time.
The data stream was first separated into 37 separate channels: each data “packet” was sent through a fiber optic core (the core of the cables). But the story doesn’t end there: each of these data packets has been further subdivided 223 times, to be associated with individual “slices” of the magnetic spectrum.
Why do we suddenly speak of the magnetic spectrum when it is a question of light? We raised the issue in our article on the first photonic processor: a press release from the University of Oxford on the subject reminded us of a fairly well-known fact: light is made up of different “wavelengths”, which can be very clearly distinguished from each other. When they are circulated in devices capable of distinguishing them, they can therefore be used as different “information channels”. In fact, optical fiber is based on this very concept: through small “cables”, the famous optical fibers, it carries the different information channels in a single ray of light.
Light, an electromagnetic wave
To go even further than this technology, various researchers have looked into another property of light, which is “polarization”. Did you think light traveled in a straight line? Nay. Instead, the light would be considered an “electromagnetic wave,” a term that refers to oscillations in the electric field. In other words, it “ripples”. It therefore has properties such as polarization: in a way, it is the “direction” associated with wave oscillations. These oscillations can be rotated in multiple directions, and a single ray of light contains multiple polarizations. Here we are ! In the same way as the different wavelengths, the scientists who designed the photonic processor were able to use these different polarizations as so many channels of information.
The scientists who worked on the photonic chip, for their part, used a “frequency comb”. “ Frequency combs are a special type of light source, characterized by their spectral composition of equidistant frequency components resembling the teeth of a comb “, explain the scientists in their work, published in Nature. By using this “frequency comb” to optimally separate frequencies, data could be transmitted all at once without interfering with each other. The chip therefore uses a single continuous laser, which is divided into several frequencies. Separate devices encode the data in each of the output streams.
It will be understood that scientists are not the first to take an interest in this type of technology to massively increase data transmission capacities. They claim, however, to have set a record in this area, while using only a single chip as a light source. In fact, the amount of data transmitted was even so large that no computer could have received so much data at once. The scientists therefore used “dummy data” for their experiment, and tested the speed channel by channel.