| 摘要 |
An OFF state, that is the maximum attenuation level, for an electro-optic attenuator/switch (14,32,36) results when either a first or second control voltage is applied to the control input. An AC generator (80,82), coupled to the control input, generates a square wave signal having minimum (V-VÀ) and maximum (V+VÀ) 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 applying a voltage pulse with a magnitude (V) 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 and allows the prevention of DC drift. |
