Effect of multiple-modes on the switching efficiency of waveguide couplers

The switching efficiency of rectangular waveguide couplers is investigated for a case where multiple-modes exist in the waveguides perpendicular to the direction of coupling but only a single-mode exists in the direction of coupling. It is found that, given a reasonable distribution of input energy over the possible modes, the existence of multiple-modes perpendicular to the direction of coupling has only negligible effects on the performance of the couplers. These results, while applicable to planar waveguide couplers, are of particular interest for vertically arranged couplers.<
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