"The main advantage of our new source is that it is small, bright and silicon based," said researcher Daniele Bajoni. "The diameter of the ring resonator is 20µm. Previous sources were hundreds of times larger than the one we have developed.
"In the last few years, silicon integrated devices have been developed to filter and route light, mainly for telecommunication applications," he continued. "Our micro-ring resonator can be readily used alongside these devices, moving us toward the ability to fully harness entanglement on a chip."
The research could find application in quantum information technologies –and quantum cryptography protocols in particular. According to Bajoni and his colleagues, these protocols have been demonstrated and tested, but what has been missing was a cheap, small, and reliable source of entangled photons capable of propagation in fibre networks.
