Enhanced Faraday and Kerr rotation in magnetic garnet gratings with defects for photonic integration

Summary form only given. Magnetic garnets such as bismuth-substituted yttrium iron garnet (Bi-YIG) are of great interest for the fabrication of optical isolators and circulators exploiting Faraday rotation. While their magnetic properties are relatively strong, nonetheless propagation lengths of order 0.5-1.0 mm are required to produce 45/spl deg/ rotations for isolation at communications wavelengths. Although such materials yield compact bulk isolators, thinner films are required for a number of integrated applications-non-guided propagation across a rotator inserted in a waveguide requires structures less than /spl ap/30 microns to control diffraction loss. We use a coupled mode equation (CME) description and exact matrix calculations to investigate the relation between rotation and output intensity. We find that appropriate placement of defects permits simultaneous optimization of both. With such structures very short high-quality isolators could be built.