U.S. and Italian physicists have developed a photonic integrated circuit capable of performing key mathematical operations for mining cryptocurrencies. It copes with them by about two orders of magnitude more effectively than specialized devices for mining bitcoin. The results of the work are published in the journal Optica.

"Right now, cryptocurrency mining is only available to people who have access to free or nearly free electricity. The energy-efficient photonic chip we created will allow people around the world to participate in mining these digital assets," said Stanford University (USA) researcher Sunil Pai, whose words are cited by the journal's press service.

The emergence of bitcoin and other cryptocurrencies and the rapid growth of these digital assets in mid-2010 led to the emergence of an entire industry for mining and selling cryptocurrency. Initially mining was done by IT enthusiasts, but about five or six years ago, giant industrial cryptocurrency "farms" emerged, built on millions of specialized chips and consuming huge amounts of energy.

These trends have led many scientists to question how much energy this industry consumes and the consequences of its existence. In particular, four years ago, researchers found that cryptocurrency production consumes more than 0.5% of the world's power plant capacity, and by 2025, Chinese miners alone will consume more than 296 terawatt hours of energy, which is comparable to the energy budget of many developed countries.

Photonic mining Researchers have proposed a solution to this problem by switching from electronic chips for mining bitcoin and other cryptocurrencies to their photonic counterpart. Driven by this idea, physicists have created an optical integrated circuit capable of calculating the various mathematical operations associated with matrix-vector multiplication, which account for most of the calculations in mining bitcoin and many other types of cryptocurrencies.

Such calculations, as found by American and Italian scientists, can be carried out with one of the varieties of interferometers. It is an optical device that allows to "subtract" one ray of light from another and determine the difference between them. The team adapted the cryptographic algorithms used in bitcoin mining to work with the interferometers, which allowed them to further simplify and speed up calculations.

Physicists have implemented this idea on a prototype photonic chip, which contains 36 optical calculators, combined in a two-dimensional network, as well as input and output data systems, error correction and various control elements. To manufacture such a device, as Pai and his colleagues point out, absolutely the same technologies that are now used to "print" conventional computer processors are needed.

Experiments showed that the prototype photon miner spent about two orders of magnitude less energy in performing key mathematical operations than its existing silicon counterparts. This will reduce the cost of electricity to produce such digital assets, the scientists concluded.