Quantum information science promises to revolutionise information and communications technologies (ICT) in the 21st century via secure communication, precision measurement, and ultra-powerful simulation and computation. The realisation of these technologies will massively enhance our ability to secure and process the ever-increasing volumes of information that drives our global economy. The ability to simulate complex systems could one day deliver new materials, pharmaceuticals and solar cells. Photonics is destined for a central role in these future quantum technologies: single particles of light --- photons --- are an ideal system for encoding, processing, and transmitting quantum information. However, the standard approach of encoding one quantum bit (or qubit) of information per photon limits current techniques to small system sizes. At these small sizes these systems are unable to fulfil their tremendous promise. This Fellowship will take a new approach --- encoding much more information per photon --- and thereby realise systems whose performance exceeds that of a conventional computer. This new approach is made possible by the earlier development at Bristol of the field of integrated quantum photonics --- the use of waveguides on silicon chips to generate and guide photons. Because these waveguide chips can be fabricated in a highly parallel way --- much like computer chips --- highly complex waveguide circuits can be relatively easily realised. By propagating many photons in quantum circuits of many waveguides this type of higher-dimensional system promises a 'fast-track' to new applications in communication, precision measurement, imaging processing and simulation.