为了实现对晶体电光系数高速率、高精度和高灵敏的测量, 提出了一种基于弹光调制的电光系数测量新方案。运用低通滤波和数字锁相技术分别提取出调制信号的直流项和一倍频项数据, 进而解调出晶体的电光系数。详细分析了该新方案的原理, 搭建了实验系统, 并对铌酸锂(LiNbO3)晶体样品的电光系数进行了测试。实验结果表明, 系统测量精度为2.3%, 灵敏度为1.7×10－14 m/V, 测量速率为每数据点100 ms。

In order to realize the measurement with high speed, high accuracy and high sensitivity of crystal electro-optic coefficients, a novel electro-optic coefficient measurement method based on photo-elastic modulation is proposed. By means of low-pass filtering and digital phase-locked technologies, the data of the DC term and the first harmonic term of the modulated signals are extracted, respectively, then the crystal electro-optic coefficient is demodulated. The principle of this new scheme is analyzed in detail, the experimental system is set up and the electro-optic coefficient of lithium niobate (LiNbO3) crystal sample is measured. The experimental results show that the measurement accuracy is 2.3%, the sensitivity is 1.7×10－14 m/V, and the measurement speed is 100 ms per data point.