Fast higher-order full-wave FEM analysis of traveling-wave optoelectronic devices

The evaluation of the microwave propagation characteristics of traveling-wave optoelectronic devices by the full-wave finite element method leads to large generalized eigenvalue equations which have to be solved for each frequency point. This paper describes a novel approach, based on the singular value decomposition, which drastically reduces the size of the eigenvalue problem without loss of accuracy. Moreover, by employing higher order elements, conductor losses are evaluated with a smaller number of unknowns, and the discontinuity of the normal field components at material interfaces is correctly modeled. The effectiveness of our numerical technique is demonstrated by discussing applications to electrooptic and electroabsorption modulators.