Method and apparatus for modulating optical energy using light activated semiconductor switches

The optical modulator of the invention comprises an electro-optic material (EOD) which modulates optical energy in accordance with an applied voltage. The applied voltage is controlled by a light activated switch, or switches, which vary the magnitude of the voltage applied by switching a charge transfer circuit (or other dc source) of which the EOD forms a capacitive element. The charge transfer circuit preferably includes a plurality of capacitive elements, each charged to a separate voltage, so that when switched by said light activated switches, the voltage applied to the EOD is controlled. When used in a laser cavity, the optical modulator can control the output of the laser in response to optical input signals. The optical modulator may be used for Q-switching the laser cavity, mode-locking the laser, cavity dumping the laser or modulating the output of the laser, or a combination of the above. The optical input control signal may comprise light from within the laser cavity, from the output of the laser cavity, or from a source external to the laser cavity. The optical modulator may modulate a plurality of beams of optical energy based upon a single applied voltage or it may modulate the plurality of beams in accordance with a respective plurality of applied voltage levels.