Semiconductor waveguides: analysis of optical propagation in single rib structures and directional couplers

Optical propagation in semiconductor waveguides has been analysed in three ways: the semi-analytic `effective index¿¿ method and two numerical methods based on variational techniques. Comparisons have been made using three semiconductor waveguide structures, and some fundamental limitations to accuracy have been identified. The techniques have also been used to calculate the transfer length for directional couplers.