AN INTEGRATED PHOTONIC MACH-ZEHNDER INTERFEROMETER WITH NO ELECTRODESFOR SENSING ELECTRIC-FIELDS

A new configuration for a Mach-Zehnder interferometric electric field sensor device utilizing the electrooptic effect is reported. The lithi um niobate device uses no metallic electrodes and operates solely by i mmersion in an electric field. Reverse poling of one arm of the interf erometer provides opposing optical phase changes in the two interferom eter arms when placed in an electric field. One fabricated device exhi bits a measured minimum detectable field of 0.22 V/m square-root Hz an d a frequency response of greater than 1 GHz. Theoretical calculations show that detection of 0.11 V/m square-root Hz is attainable while th e upper frequency limit can exceed 6 GHz.