Photonics is a leading approach in realizing future quantum technologies and recently, optical waveguide circuits on silicon chips have demonstrated high levels of miniaturization and performance. Multimode interference (MMI) devices promise a straightforward implementation of compact and robust multiport circuits. Here, we show quantum interference in a 2… (More)
Linear optics underpins fundamental tests of quantum mechanics and quantum technologies. We demonstrate a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase… (More)
We develop techniques to verify the computational complexity of a class of analogue quantum computers known as boson samplers. We demonstrate these techniques with up to 5 photons in two different types of integrated linear optical circuit, observing Hilbert spaces of up to 50,000 dimensions.
We report on a quantum key distribution (QKD) experiment where a client with an on-chip polarisation rotator can access a server through a telecom-fibre link. Large resources such as photon source and detectors are situated at server-side. We employ a reference frame independent QKD protocol for polarisation qubits and show that it overcomes detrimental… (More)
Optical quantum technologies require new photonic components to exploit integrated architecture. We demonstrate quantum interference in MMI couplers and coupled waveguides that implement two-particle quantum walks, showing unique quantum behaviour.
Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm.