Abstract: A fiber optic servoactuator control system. The system includes an actuator optical interface having light controlled electric switches for servoactuator control and for control of a solenoid and an optical modulator, all connected to a single optical fiber. The fiber is connected at its second end to a computer optical interface having three light emitters and a detector optically coupled into the single optical fiber. Only the single optical fiber and a pair of electric wires run between these two interfaces. The wires carry alternating and direct current to the actuator to power the device actuated, such as a servovalve. This system typically can be applied to the control of aircraft engines, primary flight controls, machine tools, ships and the like. The system is resistant to electromagnetic interference and pulses. The actuator may be located in a high temperature hostile environment, such as an aircraft engine.

Abstract: A lase diode light source (21) is arranged to emit light of a desired intensity (I1), which is transmitted via an optical conductor (22). Light exiting the fiber has an intensity (I.sub.2), and falls incident on the receiver surface of a photodiode (23). Such transmitted light provides both the power and control for operating a load (24). The load has a maximum impedance such that the maximum load input voltage required to produce the maximum desired load current does not exceed the forward conductive breakdown voltage of the photodiode.