A manufacturable platform for photonic quantum computing

Abstract

Whilst holding great promise for low noise, ease of operation and networking [1], useful photonic quantum computing has been precluded by the need for beyond-state-of-the-art components, manufactured by the millions [2–6]. Here we introduce a manufacturable platform [7] for quantum computing with photons. We benchmark a set of monolithically-integrated silicon photonics-based modules to generate, manipulate, network, and detect heralded photonic qubits, demonstrating dual-rail photonic qubits with 99.98% ± 0.01% state preparation and measurement fidelity, Hong-Ou-Mandel quantum interference between independent photon sources with 99.50% ± 0.25% visibility, two-qubit fusion with 99.22% ± 0.12% fidelity, and a chip-to-chip qubit interconnect with 99.72% ± 0.04% fidelity, conditional on photon detection and not accounting for loss. We preview a selection of next-generation technologies—low-loss silicon nitride waveguides and components to address loss, as well as fabrication-tolerant photon sources, high-efficiency photon-number-resolving detectors, low-loss chip-to-fiber coupling, and barium titanate electro-optic phase shifters for high-performance fast switching.