NEW OPTICAL WAVE-GUIDE POCKELS SENSOR FOR MEASURING ELECTRIC-FIELDS

An optical electric held sensor using a Pockels crystal which has the advantage of directly measuring the electric field in a space with lim ited disturbance of its distribution has been studied. We present an o ptical waveguide technique which has been developed to miniaturize the sensor. In a prototype sensor a light beam is propagated along a z-di rection waveguide in a y-cut LiNbO3 crystal. The width of the waveguid e is 7 mu m and its length is 4.39 mm. The sensor is not based on an i nterferometer but on a single waveguide. The sensor has a simple and o ptimum configuration, and its output has good linearity to applied ele ctric fields. Its frequency and temperature characteristics are presen ted. A new and smaller sensor with a waveguide 1 mm in length has been developed. It has almost the same configuration as the prototype sens or except for a smaller size. Results of measurement of ac and step el ectric fields using this sensor are presented.