Novel quantum photonic information device
Harnessing nonlinearities strong enough to allow interaction of single photons offers new possibilities for quantum information processing. Nonlinear photon pair sources produce indistinguishable photons of a well-controlled spectrum, allowing high fidelity in quantum interference. However, a lack of scalable sources that produce single photons on demand hampers research in this direction. The EU-funded project 'Integrated single-photon sources in silicon' (ISSIS) worked on integrating photon sources and waveguide circuits on a chip to provide a scalable solution. Modern silicon–photonic manufacturing platforms enabled scientists to create a photon pair generation and wavelength filtering system on a single chip. These sources were arranged in an array so that detection, feed-forward and routing could deliver single photons to an output with high certainty. ISSIS successfully demonstrated near-perfect quantum interference with a multiplexed single photon source based on nonlinear silicon waveguide interactions. To realise this compact source of single photons, scientists integrated the photon sources with optical delay lines, fast switching systems and control electronics. The project did not only succeed in its scientific objectives but also in its outreach activities. The packaging and chip-based architectures developed were used to create a unique educational tool called Quantum in the Cloud. Through this application, users can register to access a quantum processor chip and perform experiments on a simulator.
