压电效应对LiNbO_3集成光波导电场传感器频率特性的影响

Influence of Frequency Characteristics by Piezoelectric Effect on LiNbO_3 Integrated Optical Waveguide Electric Field Sensor

实验研究中发现LiNbO3集成光波导电场传感器的输出波形中叠加有频率在几百千赫兹左右的振荡信号,导致传感器探测到的电场信号发生畸变。从LiNbO3衬底的压电效应出发对这一谐振现象进行了理论分析。比较谐振频率的理论计算值和实际测量值得知,LiNbO3衬底的宽度是影响谐振的主要因素。针对一种用于雷电电磁脉冲测量的LiNbO3集成光波导电场传感器,其设计衬底宽度为3mm,再次实验发现振荡信号被抑制在-30dB以下。

In experiment it has been found that the output waveform of integrated optical waveguide electric field sensor is overlapped by interference signal with frequency of hundreds of kilohertz, which leads to a distortion of the detected electric field signal. The resonance phenomenon is analyzed theoretically based on the piezoelectric effect of LiNbO3 crystal. By comparing the resonant frequency value of theoretical calculation with that of measurement, it shows that the resonance is mainly influenced by the width of LiNbO3 substrate. For lighting impulse detecting, an integrated optical waveguide electric field sensor with 3 mm substrate width is designed and experimental results demonstrate that the resonance phenomenon has been obviously suppressed under -30 dB.