Ideal bend contour trajectories for singlemode operation of lowloss overmoded waveguides

Abstract

Bend designs for single-mode operation of low-loss overmoded waveguides are presented. A class of contour trajectories for minimum radiation loss is derived analytically, and numerical optimization is used to find ideal trajectory parameters. Three-dimensional finite-difference time-domain simulations predict bend losses below 0.1 dB for 180 -bends of overmoded silicon-on-insulator waveguides with a radius of R = 1:5 m. These findings are supported experimentally.