A single-electrode push-pull fused vertical coupler (FVC) switch using macr
oscopic crystal inversion symmetry is demonstrated. The anisotropic linear
electrooptic effect in a zinc-blende crystal is used to achieve optical swi
tching under 12-V reverse bias for a 6.9-mm-long FVC whose two guiding laye
rs have different crystal symmetries. No switching is observed for the iden
tical structure in which the two guiding layers have the same crystal symme
try.