How to tap an innocent waveguide

We study the interaction of a mode propagating in a planar waveguide with a three dimensional rectangular defect (protrusion or notch) in the structur e. The scattering by the defect disturbes the propagation of the mode and l ight is coupled out of the waveguide. To investigate these phenomena we com pute electric field distributions with the Green's tensor technique and sho w movies with varying defect geometries and different mode polarizations. T hese calculations should be useful for optimizing specific elements in comp lex photonic circuits. (C) 2001 Optical Society of America.