Nonlinear response of a gallium phosphide nanopatterned photonic waveguide in the CW regime

The third-order Kerr nonlinear response in gallium phos-phide nanoscale waveguides is measured through continuous wave (CW) four-wave mixing. The extracted nonlinear coefficient ranges from about 800 W −1 m −1 to 1400 W −1 m −1 , consistently with an estimated material nonlinearity n 2 3.5 × 10 −18 W −1 m 2. The roles of the residual absorption and the related thermal effects are discussed.