Liu, YananDong, DaoyiPetersen, IanYonezawa, Hidehiro2024-05-050005-1098http://hdl.handle.net/1885/317283Optical Parametric Oscillators (OPOs) have wide applications in quantum optics for generating squeezed states and developing advanced technologies. When the phase or/and the amplitude of the pumping field for an OPO have fluctuations due to fault signals, time-varying uncertainties will be introduced in the dynamic parameters of the system. In this paper, we investigate how to design a fault-tolerant H∞ controller for an OPO with a disturbance input and time-varying uncertainties, which can achieve the required H∞ performance of the quantum system. We apply robust H∞ control theory to a quantum system, and design a passive controller and an active controller based on the solutions to two Riccati equations. The passive controller has a simple structure and is easy to be implemented by using only passive optical components, while the active quantum controller may achieve improved performance. The control performance of the proposed two controllers and one controller that was designed without consideration of system uncertainties is compared by numerical simulations in a specific OPO, and the results show that the designed controllers work effectively for fluctuations in both the phase and amplitude of the pumping field.This work was supported by the Australian Research Council’s Discovery Projects Funding Scheme under Project DP190101566 and Project DP180101805, the Air Force Office of Scientific Research under Agreement FA2386-16-1-4065, the Centres of Excellence under Grant CE170100012, the Alexander von Humboldt Foundation of Germany, and the U. S. Office of Naval Research Global under Grant N62909-19-1-2129.application/pdfen-AU© 2022 Elsevier LtdCoherent H∞ controlQuantum opticsRiccati equationsFault-tolerant quantum controlQuantum controller202210.1016/j.automatica.2022.1102362023-01-08CC BY-NC-ND