摘要：
To increase the measurement range of optical voltage sensor, a method for regulating and increasing the half-wave voltage of bismuth germanate crystal by varying the cutting direction was proposed. With the electro-optic wave coupling theory, the dependence of half-wave voltage on crystal cutting direction was investigated. The light propagation direction and the electrical field direction of bismuth germanate crystal were determined by the crystal cutting directions. The results demonstrate that the half-wave voltage is increased to 5 times when crystal is cut along direction[-2-0.5, 2-0.5, 0]and [0.219, 0.219, 0.951]. And the half-wave voltage is increased to 12 times when crystal is cut along direction[0.140, 0.275, 0.951]and[2-0.5, 2-0.5, 0]. The influence of light propagation direction on half-wave voltage was also discussed. When bismuth germanate crystal is cut along the standard direction, the variation of half wave voltage is less than 0.06% with angle error of light propagation in the range of ±0.05π. This method of half-wave voltage regulation is also suitable for other electro-optic crystals.%提出了一种通过改变晶体切割方向,调控和提高锗酸铋晶体半波电压的方法,可以显著扩大光学电压传感器的测量范围.使用电光效应耦合波理论,分析了半波电压对晶体切割方向的依赖关系.晶体切割方向决定了锗酸铋晶体的通光方向和电场方向.分析结果表明,当晶体沿[-2-0.5,2-0.5,0]和[0.219,0.219,0.951]方向切割时,可使半波电压提高为标准切割方向的5倍;当晶体沿[0.140,0.275,0.951]和[2-0.5,2-0.5,0]方向切割时,半波电压可提高至12倍.讨论了光传播方向对半波电压的影响,锗酸铋晶体采用标准切割方向,光路角度偏移在±0.05π范围内时,半波电压的变化量小于0.06%.该半波电压调控方法同样适用于其它电光晶体.
