Second Harmonic Generation in CdSiP2 Nanowires in the Optical Frequency Regime

We report on the second harmonic generation of light in a cadmium silicon phosphide (CdSiP2, CSP) nanowire waveguide excited at the telecommunication wavelength of 1550 nm. This frequency-conversion process is studied by means of time-domain simulations that solve for the full vector fields of Maxwell's equations and which incorporate the complete second-order nonlinear coefficient tensor of the CSP crystal. Over the short length of 30 μm, the CSP nanowire waveguide produces electric field pulses having a peak-to-peak value of 116 kV/cm at a conversion efficiency of 1.6×10
^-3
. This electric field value is five times larger than that obtained in a lithium niobate nanowire waveguide having the same footprint, whereas the conversion efficiency value is 11 times higher than what is achieved in the lithium niobate nanowire. These results suggest that CSP nanowire waveguides have the potential to be used for on-chip sources of coherent optical radiation that are highly efficient given their compact structure.