Single-optical-waveguide Electric-field Sensor Using Pockels Film Crystal Estimation Using Simultaneous Measurement of Many Spectra Emitted from Electrical Discharge.

有效地利用光波导技术制作了小型化的普克尔斯器件电场传感器。本文提出了一种利用单光波导的新型电场传感器，并通过对Pockels晶体上波导的优化设计，实现了具有微米级空间分辨率的光波导电场传感器。主要结果如下：1）当光束在z切LiNbO_3晶体中沿x轴沿着传播时，使用该晶体的传感器的输出强烈地依赖于环境温度。2）为了改善上述缺点，新选择了光束在y切LiNbO_3晶体中沿沿着z轴传播的方法。实验证实，这种新方法对提高传感器性能的稳定性是有用的。3）发现决定传感器灵敏度的光直流偏置的工作点可以通过控制传感器上光路的长度来容易地调节。4）试验基础上的场传感器由具有7 μ m宽的光波导的普克尔斯晶体组成，深3 μ m、长4.39mm、波长1.31 μ m的激光二极管、薄膜偏振器、光纤和光电探测器。5）对传感器施加交流电压和脉冲电压以评估其性能。实验证实，传感器在雷电脉冲区域具有良好的线性度和对高频的良好响应性。

Optical waveguide technique is effectively utilized to make a smaller Pockels device electric field sensor. Optical waveguide electric field sensors using Pockels device which are expected to have spatial resolution of micrometers are developed.In this study, a new electric field sensor using a uni-optical-waveguide is proposed and is finally realized by means of an optimum design of a waveguide on a Pockels crystal. The main results are as follows.1)When a light beam is propagated along a x-axis in a z-cut LiNbO_3 crystal,an output of the sensor using the crystal strongly depends on ambient temperature.2)In order to improve the disadvantage mentioned at the previous item, a method of propagating a light beam along z-axis in a y-cut LiNbO_3 crystal is newly chosen. It is experimentally confirmed that the new method is useful for increasing the stability of the sensor performance.3)It is found that the working point of optical dc bias which determines the sensitivity of the sensor can be easily adjusted by controlling the length of an optical path on the sensor.4)The field sensor on a trial basis consists of a Pockels crystal having optical waveguide of 7 mum in width, 3mum in depth and 4.39mm in length, a laser diode of 1.31mum in wavelength, a membrane polarizer,an optical fiber, and a photo-detector.5)Ac and impulse voltages are applied to the sensor in order to estimate the performance of it. A good linearity and a good responsibility up to a high frequency in a lightning impulse region is confirmed experimentally.