抄録
An optical electric field sensor using Pockels device has the advantages of directly measuring the electric field in space and of hardly disturbing the field distribution by inserting the sensor, and an optical waveguide technique has been introduced to miniaturize the sensor.
The sensor based on Mach-Zehnder interferometer, which was developed first, utilizes an interference between two light beams which propagate in two waveguides. Its configuration is simple, but the sensitivity to an applied electric field is not necessarily high. The second sensor using a single waveguide on a z-cut LiNbO3 crystal utilizes an interference between TE and TM mode which propagate in the waveguide. Its sensitivity to an applied electric field is high, but it has an instability owing to a thermal disturbance.
In the new sensor, a light beam travels along a single z-direction waveguide on a y-cut LiNbO3 crystal. The width of the waveguide is 7 μm and its length is 4.39mm. Its configuration comes to be more simple than previous ones. The sensor has a good linearity of its output to applied electric fields, a good response for AC and impulse electric fields and a robustness to thermal disturbances.
