设计了一种采用径向偏振光栅实现线性测量的光学电压传感器。将光学晶体的电光相位延迟角转化成环形光斑的同步旋转,由图像转换器将环形光斑转换为条形光斑,通过图像采集系统定位条形光斑暗纹的中心位置来获得被测电压值。应用琼斯矩阵证明了光斑暗纹中心位置与晶体电光相位延迟角之间的线性关系,给出了计算方法,并给出了锗酸铋(BGO)晶体和铌酸锂(LN)晶体的实验验证。结果表明该光学电压传感器的测量模式与光强无关,可直接测量172°的电光相位延迟角,测量误差小于0.5%,实现了对电压的线性测量。
An optical voltage sensor for voltage linear measurement using radial polarization grating is designed. The electro-optic phase delay in a crystal is converted into a synchronous rotation of a ring-shaped facula. The ring-shaped facula is changed into a stripe facula by an image converter, and then the applied voltage can be measured by positioning the dark stripe center with an image collecting system. The linear relation between the electro-optic phase delay and the position of the dark stripe center is proved using Jones matrix.The calculation method and the experimental verification of the bismuth germanium oxide( BGO) crystal and lithium niobate( LN)crystal are given. The results show that the measurement mode of the designed optical voltage sensor is irrelevant to the light intensity,and the measurable range of the electro-optic phase delay reaches 172°, while the linear measurement for voltage is realized with a measurement error less than 0. 5%.