Parallel Architecture of a Frequency Comb Qudit Quantum Processor

Quantum optical frequency combs provide an intriguing approach to high-dimensional quantum states. Because of the need to move probabilities among different colors, the realization of gates appropriate to multicolor photons requires nonlinear or electro-optic mixing. This paper describes a novel architecture for such gates. The parallel arrangement of mixers by dimension allows graceful scaling beyond two-dimensional qubits. The parallelism of the implementation simplifies the programming of the gate for a particular operation. As an example, we demonstrate the design of a four-dimensional Chrestenson operator.