Eigenmode analysis of optical switches in LiNbO/sub 3/-theory and experiments

The alternating electrode voltage directional coupler is analyzed by using the orthogonal symmetric and antisymmetric eigenmodes of a parallel waveguide structure. Then, conventional coupled-mode theory can be applied without modification of coupling constants. Lateral and longitudinal symmetry of electrodes and waveguides is assumed. In particular, a specific Ti:LiNbO/sub 3/ coupler is considered. It is found that the orthogonal eigenmode description leads to a different explanation of the operational principle of the so-called Delta beta coupler, as compared to conventional analysis in terms of nonorthogonal individual guide modes.<
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