BGO晶体的固有线性双折射及其温度特性严重制约着光学电压互感器(OVT)的实用化进程, 对其进行定量研究有助于提高和改进OVT的性能。文中提出了一种晶体劈干涉条纹图像法, 通过测量干涉条纹的移动实现对BGO晶体内部固有线性双折射及其温度特性的准确测量。文中采用琼斯矩阵对测量原理进行了推导, 并给出了测量实例和验证结果。结果表明, 单位长度的BGO晶体固有线性双折射会给OVT带来约1.0%的测量误差; 考虑温度特性, 误差约为1.2%, 对于OVT必须具备0.2%的测量准确度是一个严重挑战。文中提出的方法与传统的光强法比较, 不受光源功率波动的影响, 在测量过程中无需调节光学元件, 不会引入额外的误差, 测量准确度提高了约一个数量级。

The intrinsic linear birefringence and its temperature characteristic of the BGO crystal seriously restricts the development of optical voltage sensor, thus the study on the intrinsic linear birefringence is of great significance to improve the performance of the optical sensors. An interference fringes method employing a crystal wedge was proposed in this paper, and the measurement for the intrinsic linear birefringence of the crystal inside the sensing head can be realized by measuring the fringes′ displacement. The theoretical deduction of the measuring principle was given taking Jones matrix as a mathematical tool, the application example and the verifying results were also given, which indicates that the intrinsic linear birefringence and its temperature characteristic can introduce an error of about 1% to the voltage sensor. Compared with the traditional intensity method, the measured results of this method are insensitive to the power fluctuation of light source, and there is no adjustment of any optical components during the whole experiment, so no additional error will be induced. The measurement accuracy is improved by about one order of magnitude.