Ideal Bend Contour Trajectories for Single-Mode Operation of Low-Loss 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 180deg-bends of overmoded silicon-on-insulator waveguides with a radius of R=1.5 mum. These findings are supported experimentally