Enhanced quasi-phase-matched second-harmonic generation in a silicon-organic hybrid microring resonator

An enhanced second-harmonic generation process in a dually resonant silicon-organic hybrid microring resonator is presented. The necessary phase matching is fulfilled through quasi-phase matching by periodically altering the spatial distribution of the second-order nonlinearity ${\chi ^{(2)}}$χ⁽²⁾ of polymer infiltrated into a slot layer along the microring resonator propagation length. Absolute conversion efficiency up to ${P_{2\omega }}/{P_\omega } = {38}\% $P_2ω/P_ω=38% with only 10 mW pump power at $\lambda = 3.1\;{\unicode{x00B5}{\rm m}}$λ=3.1µm is obtained in an optimized structure, which shows a ${\sim}{76}$∼76-fold improvement compared to that of the straight waveguide. Also, our efficiency is comparable to that of previous works, even with the much lower pump power. We expect that our device will provide a potential application for bridging the mid-infrared and near-infrared bands on silicon photonics platforms.