Quasi-reciprocal reflective digital closed-loop optical voltage sensor

Optical voltage sensor is an important voltage sensing instrument which has been widely applied because of its unique advantages. We have proposed and accomplished a new type of quasi-reciprocal reflection type integrated optical voltage sensor, using Y-cut LiNbO₃ waveguide based on Ti-diffused technique as the electric field sensor. All digital closed-loop negative feedback detection technology and digital filtering technology have been used to improve the dynamic range and linearity, the alternating current (AC) and direct current (DC) voltage which is benefit to temperature compensation and AC signal measurement are separated. The reciprocity of light path is good. Under the power-frequency voltage of 1.4~4600 V, the nonlinear error of measurement is less than 0.35% and transformation ratio error is less than 1% as AC voltage changing from 80~4600 V.