A normalized approach to the design of low-loss optical waveguide bends

A normalized approach for optimal design of abrupt junctions between straight and curved waveguides operating in the whispering gallery mode regime is presented. The optimization includes the widths of both the straight and the curved waveguides, the lateral offset between them, and the bending radius of the curved waveguide. With this approach, optimum bend design is possible from a simple set of formulas or normalized graphs. Predicted transmission losses for optimally designed junctions are well below 0.1 d