We investigate enhancement of magnetooptical rotation in periodic magnetic garnet thin-film stacks with defects using a combination of coupled-mode theory and matrix calculations. We prove that a combination of high rotation per unit length and high output is unattainable for a symmetric grating with a single central defect. We demonstrate that the addition of a second defect introduces sufficient degrees of freedom to allow high transmission for a much larger range of rotation angles than was previously possible. We present a number of designs with emphasis on achieving 45 rotation in very short propagation lengths.
M. J. Steel, M. Levy, and R. M. Osgood, "Photonic Bandgaps with Defects and the Enhancement of Faraday Rotation," J. Lightwave Technol. 18, 1297- (2000)