Kerr nonlinear coefficient measurement of low-loss double-stripe silicon nitride waveguides

Multi-layer Si 3 N 4 waveguides, also known as Triplex waveguide technology, are a very promising waveguide platform for applications in microwave photonics and quantum photonics due to their low loss and compact circuit footprint. However to date, the Kerr nonlinearity of these multi-layer waveguides, in particular the asymmetric double-stripe (ADS) Si 3 N 4 waveguides, has not been well-investigated. Here, we performed an experimental investigation of the Kerr nonlinearity of ADS Si 3 N 4 waveguides through four-wave mixing (FWM) experiments. We obtained the nonlinear coefficient for this waveguide to be γ ADS = 0.336 ± 0.023 W -1 m -1 . When combined with low propagation loss and absence of two-photon absorption, this moderate nonlinearity can be harnessed for chip-based nonlinear signal processing and quantum photonics.