A Two-Dimensional LiNbO3 Photonic E-Field Sensor Using Inclined Dipole Antennas

A novel integrated opto-electric sensor for detecting two-dimensional (2-D) electric field (E-field) vector utilizing two inclined dipole antennas on one lithium niobate (LiNbO
₃
) substrate is proposed and demonstrated. Two tapered antennas with inclination angles of 45° and 135° are fabricated on different Mach-Zehnder interferometer (MZI) optical waveguides so as to induce local E-fields within antenna gaps to modulate optical waves for separately measuring two E-field components. Experimental results show that polarization directions of the two inclined antennas are orthogonal. The minimum detectable E-field strength is 1.56 and 0.90 V/m for two MZIs, and the fabricated E-field sensor has a wideband frequency response from 1 to 6 GHz with ±8-dB fluctuations. The proposed integrated LiNbO
₃
photonic E-field sensor has the potential of 2-D E-field vector measurement.