Induced nonlinear frequency shift of an active ring resonator on a magnonic crystal

The nonlinear shift of the resonant frequencies of a microwave active ring resonator (ARR) induced by a pump wave has been studied for the first time. The resonator was designed according to the scheme in the form of a closed ring containing a spin-wave delay line made on the basis of a one-dimensional magnonic crystal, as well as a microwave amplifier in a feedback circuit. It is shown, that with an increase in the power of the pumping wave, the shift of the resonant frequencies of the ARR increases in different ways depending on the position of the pumping frequency. The maximum induced nonlinear frequency shift is observed if the pumping frequency is at the minimum of the ARR transmission coefficient. A model describing the studied effect is developed.