The semi-collinear interaction between optical waveguide modes and backward volume magnetostatic waves

Observation of the interaction between the guided optical modes and the backward bulk magnetostatic waves (MSW) in the YIG-GGG dielectric waveguide in the semicollinear geometry is reported. The behavior of the peaks of the maximum coupling between the optical modes at high levels of microwave power is interpreted in terms of MSW nonlinearity. It is pointed out that the angle between the direction of propagation of light and the direction of propagation of the MSW is an important parameter which determines the frequency response and the efficiency of the interaction between the guided light and the MSW. For the case of backward bulk MSW, the semicollinear geometry is a reasonable compromise in achieving frequency response close to that for the collinear geometry without considerable decrease of the efficiency of interaction. The peaks of the efficient conversion of the optical modes by the backward bulk MSW exhibit a shift towards stronger bias magnetic fields