Coherent-feedback control strategy to suppress spontaneous switching in ultra-low power optical bistability

An optical resonator with intracavity Kerr nonlinearity can exhibit dispersive bistability suitable for alloptical switching. With nanophotonic elements it may be possible to achieve attojoule switching energies, which would be very attractive for ultra-low power operation but potentially problematic because of quantum fluctuation-induced spontaneous switching. In this Letter I derive a quantum-optical model of two Kerrnonlinear ring resonators connected in a coherent feedback loop, and show via numerical simulation that a properly designed ‘controller’ cavity can significantly reduce the spontaneous switching rate of a bistable ‘plant’ cavity in a completely embedded and autonomous manner.