Researchers move quantum computing to silicon

LONDON – Quantum computing has been brought a step closer to mass production by a research team led by scientists from the University of Bristol that has made a transition from using glass to silicon.

The Bristol team has been demonstrating quantum photonic effects in glass waveguides for a number of years but the use of a silicon chip to demonstrate photonic quantum mechanical effects such as superposition and entanglement, has the advantage of being a match to contemporary high volume manufacturing methods, the team claimed.

This could allow the creation of hybrid circuits that mix conventional electronic and photonic circuitry with a quantum circuit for applications such as secure communications.

One result could be that quantum mechanical computing could be deployed much sooner that had previously predicted. It has been estimated that it could take a decade or more to develop and deploy all the circuitry for an end-to-end quantum computer although such a machine would theoretically have much greater performance than current electronic computers for solving very complex problems.

The Bristol researchers' latest work, carried out with collaborators from Toshiba central R&D in Japan, Heriot-Watt University in Scotland and Delft University in the Netherlands, created a silicon-on-insulator chip with circuits to demonstrate two-photon quantum interference and photon entanglement in a Mach-Zehnder interferometer. These new circuits are compatible with existing optical fiber infrastructure and are ready to be deployed directly. The silicon waveguides have widths of 450-nm and depths of 220-nm.

"Using silicon to manipulate light, we have made circuits over 1000 times smaller than current glass-based technologies. It will be possible to mass-produce this kind of chip using standard microelectronic techniques, and the much smaller size means it can be incorporated in to technology and devices that would not previously have been compatible with glass chips," said Mark Thompson, deputy director of the Centre for Quantum Photonics in Bristol University's School of Physics, in a statement.

Thompson told EE Times that quantum secure communications could deployed commercially within five years. Over the same sort of period the Bristol research team expects to demonstrate quantum computing chips developed to solve specific problems. Many of these may be particular to molecular, atomic and even quantum simulation or to some fundamentally hard-to-solve problems in mathematics, Thompson said.

The Bristol research team is in discussions with Nokia about the use of quantum computing for use within secure mobile communications.


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