Fig. 1. Schematic views of the investigated PCW geometries (W1-PCW, NS-PCW and WS-PCW). a=400  nm, h=260  nm. Other parameters are specified in the text.

Fig. 2. Dispersion curves of the three PCWs described in Fig. 1: (a) W1-PCW, (b) NS-PCW, and (c) WS-PCW.

Fig. 3. Waveguide mode group index (nG) and dispersion coefficient (β2) of the three investigated PCWs (see Fig. 1): (a) W1-PCW, (b) NS-PCW, and (c) WS-PCW.

Fig. 4. Nonlinear properties parameters versus group indices: (a) mode field/silicon overlap factor, (b) effective nonlinear susceptibility in terms of real and imaginary parts, (c) nonlinear waveguide parameter (real and imaginary parts).

Fig. 5. FOMTPA in the three investigated structures. Black, red, and blue curves represent the parameters in W1-PCW, NS-PCW, and WS-PCW, respectively.