Producing finely tuned particles of light for high-speed computing is a complex and time-consuming process, but now a novel solution could make the fabrication of these photons faster and easier. Advanced computing technologies — such as optical quantum computers and ultrasecure communication systems — use light to quickly relay information. For these technologies to work, a photon must be tightly coupled with another photon. This is known as an entangled photon pair. Current methods to produce such pairs use relatively bulky optical equipment in specialized labs. The photons also are extremely delicate to construct and are very sensitive to mechanical vibrations. This complexity and the associated cost make it difficult to use this technology in homes or offices. The semiconductor chip schematic is a depiction of the integrated circuits designed by the Helmy research group, where the chip takes in photons from an external source (blue) and through the intricate design of the circuit. The result is two photons (red) that are entangled without the need for other circuitry or components. (Image: University of Toronto) Engineers led by professor Amr Helmy of the Edward S. Rogers Sr. Department of Electrical and Computer Engineering at the University of Toronto have designed an integrated counterpart to the delicate lab equipment that could produce entangled photon pairs using an integrated circuit. They suggest that the entire production of the photon could be completed using a single chip. They tested the first generation of the devices with their colleagues at the University of Waterloo and at Universität Innsbruck in Austria. While other attempts at creating a chip-based solution did not permit the addition of other components, Helmy’s team used a semiconductor chip that functioned with other existing equipment. Their findings show that all of the required components that traditionally exist in a lab can be on a single chip. Using quantum optical computing will be key in solving difficult computational problems such as complex data sorting. Producing entangled pairs using this chip is the first and significant step toward making them commercially available and could perhaps lead to future quantum-optical gadgets. “The research offers the prospect of unleashing the potential of the powerful and underutilized quantum technologies into the mainstream commercial world, out of the lab,” Helmy said. The findings were reported in Physical Review Letters. For more information, visit: www.engineering.utoronto.ca