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

An optical resonator with intracavity Kerr nonlinearity can exhibit dispersive bistability suitable for all-optical switching. With nanophotonic elements it may be possible to achieve attojoule switching energies, which would be very attractive for ultralow power operation but potentially problematic because of quantum fluctuation-induced spontaneous switching. In this letter I derive a quantum-optical model of two Kerr-nonlinear 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. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3589994]