LAUSR

This study investigated the optical behavior of ultra-small microdisks with radius of approximately 1 μm. We will show that the optical behavior of these disks differs from the optical behavior of larger disks. Initially, the wave resonance in a microdisk coupled to a straight waveguide was simulated numerically using the boundary element method (BEM). This method is a perfect choice for such simulation not only because of restriction of BEM meshing to disk boundary, but also because of its ability to properly model the rough edges. Then, the conventional matrix model for the microdisk optical behavior was modified by introducing a coefficient to account for the wave loss at the coupling area. The loss and coupling parameters and the quality factor were calculated by comparing the numerical results with the results of the modified matrix model. The results indicate that the coupling loss in ultra-small microdisks is significant and cannot be ignored. In the end, the effect of edge roughness on the optical behavior of the disk was investigated. The disk edges were modeled with random roughness to make the simulation more realistic. The results show that conventional matrix models are not suitable for analysis of rough-edged disks and are only applicable to the cases where disk edges are relatively smooth.