Design of Low-Loss Compact 90 degrees Bend Optical Waveguide for Photonic Circuit Applications in SOI Platform

The modal transition loss between straight and 90 degrees bend rib waveguide structures on Silicon-on-Insulator platform have been optimized with the simulated results using Finite Element Method (FEM) and Beam Propagation Method (BPM). We have studied different asymmetric configurations to minimize the radius of curvature of bend waveguide. The simulation results shows that a 90 degrees bend waveguide is possible with a bending radius as low as 800 mu m keeping the loss budget to similar to 1 dB.