2022/10/17 by Yi Zhang, Zhang, Yi, Juniyali Nauriyal +11 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Advanced Fiber Laser Technologies #Applied Physics (physics.app-ph) #FOS: Physical sciences #Nonlinear Optical Materials Research #Optics (physics.optics) #Photonic and Optical Devices
paper · pdf · doi:10.48550/arxiv.2210.09374
openalex publication_date 2022/10/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The lack of a bulk second-order nonlinearity (\chi(2)) in silicon nitride (Si3N4) keeps this low-loss, CMOS-compatible platform from key active functions such as Pockels electro-optic (EO) modulation and efficient second harmonic generation (SHG). We demonstrate a successful induction of \chi(2) in Si3N4 through electrical poling with an externally-applied field to align the Si-N bonds. This alignment breaks the centrosymmetry of Si3N4, and enables the bulk \chi(2). The sample is heated to over 500°C to facilitate the poling. The comparison between the EO responses of poled and non-poled Si3N4, measured using a Si3N4 micro-ring modulator, shows at least a 25X enhancement in the r33 EO component. The maximum \chi(2) we obtain through poling is 0.24pm/V. We observe a remarkable improvement in the speed of the measured EO responses from 3GHz to 15GHz (3dB bandwidth) after the poling, which confirms the \chi(2) nature of the EO response induced by poling. This work paves the way for high-speed active functions on the Si3N4 platform.