Photonic-Assisted Field-Probing Receiver for Kilowatt Peak-Power Wideband Radiative Wireless Transmitter

In this paper, a field-probing receiver that can be used to measure radiating fields from the phased-array transmitter which generates 1-kW peak pulsed output is presented. It consists of polarization controller, optical circulator, optical amplifier, photodiode, low-noise amplifier, distributed feedback laser diode, and optical power meter. The probe consists of an optical interferometric waveguide on a lithium niobate electro-optic (EO) substrate in the folded Mach-Zehnder (MZ) style. On the waveguide, multi-electrode array is fabricated to enhance the EO modulation depth of the MZ scheme. The electrodes serve as a micro-dipole antenna which electrically induces electric field onto the optical waveguide. The probe is fairly transparent to electromagnetic fields to minimize the level of field invasiveness, and it is fabricated with compact dimensions of 10 mm x 3 mm x 1 mm. The proposed electric probe has been experimentally validated by electric field measurements on a phase-array transmitter with a sensitivity enhancement of about 14 dB in 12 GHz compared to a commercial electric probe.