In what has been described as a major step forward in the race to build a quantum computer, engineers from the University of Bristol have, for the first time, been able to produce and control single particles of light (photons) on the same chip as other essential components.
While previous attempts have required external light sources to generate the photons, the device created by the Bristol team is the first to integrate components that can actually generate photons on-chip. "We were surprised by how well the integrated sources performed together," said researcher Joshua Silverstone. "They produced high quality identical photons in a reproducible way, confirming that we could one day manufacture a silicon chip with hundreds of similar sources on it, all working together. "This could eventually lead to an optical quantum computer capable of performing enormously complex calculations." The chip was fabricated by Toshiba, with the help of researchers from Stanford University, the University of Glasgow and TU Delft in the Netherlands. Project leader Mark Thompson said: "Single-photon detectors, sources and circuits have all been developed separately in silicon but putting them all together and integrating them on a chip is a huge challenge. "Our device is the most functionally complex photonic quantum circuit to date, and was fabricated by Toshiba using exactly the same manufacturing techniques used to make conventional electronic devices." Looking forward, the team is planning to integrate the other remaining necessary components onto the chip, and show that large scale quantum devices using photons are in fact possible. "Our group has been making steady progress towards a functioning quantum computer over the last five years," said Thompson. "We hope to have a photon based device which can rival modern computing hardware for highly specialised tasks within the next couple of years."