Numerical study on an asymmetric guided-mode resonant grating with a Kerr medium for optical switching

Optical switching effects of a guided-mode resonant grating (GMRG) with a Kerr medium have been simulated with the nonlinear finite differential time domain (FDTD) method. An asymmetric waveguide grating with a large second spatial harmonic component has been proposed for the optical switch. Resonant reflection occurs at both of the band-edge wavelengths. These wavelengths are used for the pump light and the probe light. The enhanced electric field of the pump light changes the resonant wavelength for the probe light as a result of the Kerr effect. We designed the GMRG with resonant wavelengths of 1489.6 and 1630 nm, which were used for the pump light and the probe light, respectively. When the grating material has a third-order susceptibility chi(3) of 8.5 x 10(-10) esu, the transmittance of the probe light changes from 0 to 80% by increasing the intensity of the pump light from 0 to 60 kW/mm2.