I present an experimental realization of a coherent-feedback control system that was recently proposed for testing basic principles of linear quantum stochastic control theory [M. R. James, H. I. Nurdin, and I. R. Petersen, e-print arXiv:quant-ph/0703150v2, IEEE Transactions on Automatic Control (to be published)]. For a dynamical plant consisting of an optical ring resonator, I demonstrate $\sim 7\mathrm{dB}$ broadband disturbance rejection of injected laser signals via all-optical feedback with a tailored dynamic compensator. Comparison of the results with a transfer function model pinpoints critical parameters that determine the coherent-feedback control system’s performance.

• Received 13 March 2008

DOI:https://doi.org/10.1103/PhysRevA.78.032323