An OFF state, maximum attenuation level, for an electro-optic attenuator/switch results when either a first or second control voltage is applied to the control input. An AC generator, coupled to the control input, generates minimum and maximum peak voltages that correspond to the first and second control voltages, respectively, so that the maximum attenuation level of the light beam being switched is provided by the electro-optic attenuator while either of the minimum and maximum peak voltages is applied to the control input. An ON state is achieved by introducing a voltage pulse with a magnitude corresponding to the minimum attenuation level. The ON voltage pulse is added to the square wave. This permits operation of the electro-optic switch in a normally OFF state without requiring a DC bias voltage.