Opto-electric device for measuring the root-mean-square value of an alternating current voltage

Abstract

An opto-electric device for measuring the root mean square value of an alternating current voltage comprises: a) an electric field-to-light-to-voltage converter having 1) a light source; 2) an electro-optic material: (a) receiving light from the light source; (b) modulating said light; and (c) providing a modulated light output; 3) an electric field applied to the electro-optic crystal to modulate the light from the light source to produce the modulated light output; b) an optical receiver for receiving and converting the modulated output light from the electro-optic material to a first voltage that is proportional to a square of the electric field applied to the electro-optic material; c) an averager circuit receiving the first voltage and providing a second voltage that is proportional to the average of said square of said electric field over a period of time; and d) an inverse ratiometric circuit receiving the second voltage from the averager circuit and returning a third voltage that is an inverse voltage of the second voltage to the electric field-to-light-to-voltage converter to produce an output voltage that is the root mean square voltage of the applied electric field. The device uses a Mach_Zehnder interferometer operating a a square law device and features a housing for maintaining the interferometer at constant temperature using a temperature control unit. A nulling circuit is provided to maintain the interferometer at it null operating point as are calibration circuits to correct for voltage amplitude and frequency changes.

Dependencies are inferred from the claim text.