Bending efficiency analysis of horizontal single- and multiple-slot waveguide microrings

The bending efficiencies of three-dimensional (3D) horizontal single- and multiple-slot waveguide microrings are analyzed using the effective index and modified transfer matrix methods. The effects of waveguide parameters, low-index material, high-index material, asymmetric structure, and asymmetric slots on the bending loss are studied. The results show that the bending efficiency can be enhanced by applying asymmetric structures and asymmetric slots. In addition, it is demonstrated that the bending loss increases with the increase of the number of slots. However, by using proper thicknesses for different high-index layers of the horizontal multiple-slot waveguide, it is possible that the horizontal multiple-slot waveguide can provide a lower bending loss than the single-slot one.