Microwave Bistability in Active Ring Resonators With Dual Spin-Wave and Optical Nonlinearities

The microwave bistability in active ring resonators (RRs) with dual spin-wave and optical nonlinearities has been investigated. The theory for the nonlinear transfer function of the active RRs consisting of the spin-wave delay line and highly nonlinear optical fiber was developed taking into account both the dispersion and nonlinear properties of the ferrite film as well as the nonlinear properties of the optical fiber. The bistable behavior of the transmission characteristics of the active RR was analyzed using the developed theory for two types of spin-wave delay lines based on forward volume spin waves (FVSWs) and surface spin waves (SSWs). It was shown that an introduction of highly nonlinear optical fiber in the active RR based on the FVSW delay line provides compensation of the spin-wave nonlinearity. However, exactly the same nonlinear optical fiber in the active RR based on the SSW delay line enhanced the bistability. The transmission characteristics of the particular case of the active RRs consisted of the nonlinear FVSW or SSW delay lines, and linear optical single-mode fiber was experimentally measured. The obtained theoretical results are in good agreement with the experiment.