Magnetic garnet films can be used as optical waveguides in the near infrared region. Light propagates in the waveguides as TE or TM modes. Due to the linear and circular magnetic birefringences these modes are coupled depending on the direction of the magnetization with respect to the direction of mode propagation. The efficiency of the mode conversion caused by the coupling is calculated. If the ferrimagnetic resonance is excited in the waveguide, a dynamical TE-TM mode conversion and thus a modulation of the light is induced. The spectrum of the modulated light contains besides the fundamental frequency higher harmonics. For a gallium-substituted film of yttrium iron garnet the dynamical mode conversion is measured for different orientations of the magnetization. A modulation efficiency of 6% at a frequency of 1 GHz is achieved. The experimental results are in qualitative agreement with calculations.

Date Published: 31 January 1989
PDF: 6 pages
Proc. SPIE 1018, Electro-Optic and Magneto-Optic Materials, (31 January 1989); doi: 10.1117/12.950006

Published in SPIE Proceedings Vol. 1018:
Electro-Optic and Magneto-Optic Materials
Jean-Pierre Huignard, Editor(s)