Dynamic conversion of waveguide modes in the regime of nonlinear ferromagnetic resonance

Dynamic conversion of waveguide modes in a magnetogyrotropic waveguide in t he regime of uniform spin precession taking into account nonlinear magnetiz ation dynamics for large precession angles is studied. It is shown that the magnetization vector nutation is caused by precession frequency doubling, which increases the modulation depth of laser radiation. Harmonics with fre quencies equal to multiples of the fundamental frequency of the ferromagnet ic resonance are considered, and their contribution to the total efficiency of mode conversion for an arbitrary direction of the equilibrium magnetiza tion direction is analyzed.