High-efficiency and broadband wavelength conversion in a slot waveguide with the periodic structure altering the phase-mismatch

High-efficiency wavelength conversion based on the quasi-phase-matching technique is proposed and simulated in a slot waveguide. Benefit from the tight light confinement and the high nonlinear material (silicon nanocrystal) filled in the slot region, a large nonlinear coefficient is achieved. With the linear phase-mismatch alternately changing between two values of the opposite signs, periodical attenuation of the idler power is suppressed even in the presence of severe dispersion. Numerical simulation shows that an efficiency of -12.3 dB at 1850 nm and a 3-dB bandwidth of 484 nm are available for the 1550 nm-wavelength pump in a 4 mm long silicon slot waveguide.