Programmable ultra-broadband photonic chaos platform enabled by microwave-chaos-driven electro-optic frequency combs

Abstract: Optical chaos holds great promise for secure communication, LiDAR, and reinforcement learning. However, its scalability has long been constrained by an intrinsic trade-off between bandwidth and the number of parallel chaotic channels. Here, we introduce a programmable "chaos-on-comb" architecture that overcomes this limitation using standard electro-optic components. By heterodyning a delayed-feedback chaotic laser with a continuous-wave reference, a broadband chaotic microwave signal is generated to simultaneously drive a cascaded electro-optic comb, imprinting chaotic dynamics across all comb lines and merging them into an ultra-broadband chaotic continuum. Then, incorporating spectrum slicing enables flexible extraction of parallel chaotic channels with preserved statistical independence and per-channel programmability. As a result, we demonstrate a single-channel ultra-broadband optical chaos with an effective bandwidth of 543.8 GHz, and a broadband terahertz noise source with an excess noise ratio of 52.99 \pm 2.85 dB to validate its flatness. Furthermore, we employ the uncorrelated parallel chaos for ultrafast photonic decision-making in a 256-armed bandit problem, achieving a favourable power-law scaling exponent of 0.86. Our work paves the way toward programmable, reconfigurable, and application-ready photonic chaos systems.