Electric-field poling of a silicon nitride microring resonator for linear electro-optic modulation

The centrosymmetric structure of stoichiometric silicon nitride inhibits the realization of second-order nonlinear processes in this low-loss, complementary-metal-oxide-semiconductor fabrication-compatible platform. Nevertheless, linear electro-optic modulation is an essential functionality desired for implementation in photonic integrated circuits. This study presents the successful achievement of electro-optical modulation in a silicon nitride microring resonator, employing thermally assisted electric-field poling. With an inscribed electric field of 100 V/μm within the silicon nitride waveguide, an effective second-order susceptibility of 0.45 pm/V is induced. Leveraging silicon nitride as the active material for electro-optic modulation, we determined the operational bandwidth of the device, constrained by the electrode design, to be 78 MHz. Furthermore, we demonstrate the capability of the device to modulate data at bitrates of up to 75 Mb/s. Our findings highlight the potential of linear electro-optical modulation in the silicon nitride integrated platform.