Enhanced four-wave mixing with MoS₂ on a silicon waveguide

MoS₂ is a layered quasi-2D material that can enhance effective third-order optical nonlinearity of waveguides. In this paper, we measured the optical loss of MoS₂ on silicon waveguides and compared the conversion efficiencies of four-wave mixing (FWM) in silicon waveguides with and without MoS₂ on the top cladding. Hybrid integration of the few-layer MoS₂ produced about 4 dB enhancement in the idler output of FWM. The Kerr coefficient of MoS₂ was obtained as (2.7 ± 0.2) × 10⁻¹⁶ m² W⁻¹. The refractive index of MoS₂ was obtained from the characteristics of grating couplers. (paper)