LiNbO3 Optical Waveguide Sensor for Measurement of Electromagnetic Emission

For measurement of the electromagnetic emission (EME) with larger dynamic range and broader bandwidth, two types of LiNbO3 (LN) optical waveguide (OWG) electric field sensor fusing with an OWG asymmetric Mach-Zehnder interferometer (AMZI), segmented electrode and tapered antenna have been designed, fabricated and experimentally demonstrated. By using the segmented electrode incorporated with the AMZI, the electro-optic (EO) interaction length is increased and the operation point is biased at p/2, the sensitivity has been improved tremendously. However, by using the tapered structure to form a travelling wave antenna, frequency bandwidth of the sensor has been expended. Experimental results demonstrate that the minimum detectable electromagnetic pulse (EMP) of the sensor with segmented electrode is 20 V/m in the time domain under the terminal impedance is 50 O, while frequency response is measured from 100 kHz to 10 GHz. In addition, the application for measurement of the explosive radiation EMP in the time domain reveal that the sensor is expected to be widely used in detection of the transient EME.