Calibrated 100-dB-dynamic-range electro-optic probe for high-power microwave applications

Abstract

Highly stable electro-optic field probe with wide dynamic range is presented. The highly efficient electro-optic modulation mechanism--based on interference and field-induced phase retardations using a new embodiment with a relatively thick sensor crystal mounted on a fiber--is explained. The probe is calibrated up to 3.5 GHz through the use of a micro-TEM cell and a standard gain horn antenna, both devices in which the electric field may be calculated at the specific sensing location of an electro-optic probe. The field-calibrated sensor shows over 100 dB (≤ 1 V/m to > 100 kV/m) of linear dynamic range. Also, an issue with the instability of the sensors that often occurs in intense electric-field measurements associated with electro-optic crystals is overcome by a real-time, bias-control loop. The stabilized sensor performance and its potential use for (pulsed) high-power-microwave applications are discussed.