Switching characteristics of directional couplers with a longitudinal electrode gap

The effect of passive phase shift regions on the performance characteristics of parallel waveguide couplers is considered. In particular, a longitudinal electrode gap in addition to phase shifts in the adiabatic input and output taper regions is considered. Both types of phase shifts have a degrading impact on the accessibility of some switching states. However, an electrode gap combined with taper region phase shifts may be beneficial for certain traveling wave electrode configurations. For a certain combination of gap and electrode lengths a through state with better than 30 dB crosstalk over an extended voltage range has been identified.<
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