High-dimensional topological photonic entanglement

The generation and manipulation of high-dimensional quantum states lies at the heart of modern quantum computation. The use of topology to resiliently encode and transport quantum information has been widely investigated in condensed matter and has recently penetrated quantum photonics. However, a route to scale up to a large number of entangled topological photonic modes has been missing. In this work, we demonstrate a method to generate high-dimensional topological photonic entanglement. Our platform relies on designed silicon photonic waveguide topological superlattices, which support nonlinear generation of energy-time-entangled photon pairs on a superposition of multiple topological modes. We show strong signatures of entanglement of up to five topological modes with resilience to nanofabrication imperfections, providing a route toward scalable, fault-tolerant quantum photonic states.