Single-Mode Behaviour Judgment of Optical Waveguides by Imaginary-Distance Beam Propagation Method Under Perfectly Matched Layer Boundary Condition

Imaginary-distance beam propagation method under the perfectly matched layer boundary condition is applied to judge single-mode behaviour of optical waveguides, for the first time to our knowledge. A new kind of silicon-on-insulator-based rib structures with half-circle cross-section is presented. The single-mode behaviour of this kind of waveguide with radius 2 μm is investigated by this method. It is single-mode when the slab height is not smaller than the radius.