Mirko Lobino , University of Bristol
Abstract
Until recently, quantum photonic architecture comprised of large-scale (bulk) optical elements, leading to severe limitations in miniaturization, scalability and stability. We developed the first integrated quantum optical circuitry, demonstrating high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits, including two-photon quantum interference with a visibility of 99.5(4)% and a controlled-NOT gate with an average logical basis fidelity of 96.9(1)%. We use these devices to demonstrate multi-photon effects relevant to quantum metrology, quantum information processing, and quantum measurement. The monolithic nature of these devices means that the correct phase can be stably realized in what would otherwise be an unstable interferometer, greatly simplifying the task of implementing sophisticated photonic quantum circuits. The first integrated quantum metrology experiments are demonstrated by beating the standard quantum limit with two- and four-photon entangled states while demonstrating the first re-configurable integrated quantum circuit capable of adaptively controlling levels of non-classical interference of photons.