Fig. 1. (a) Sketch of 2D SWG considered in the 2D-FDTD simulations. (b) Sketch of 2D slot Bragg grating structure considered in the 2D-FDTD simulations. Period of grating a and width of air groove Wair is denoted in the figure. (c) Incident E-field profile in the 2D-FDTD slot Bragg grating simulations. The LN slot, silicon rails, and air ambient medium are denoted, respectively, in the figure. (d) Normalized transmission of 2D slot Bragg grating structure with parameters of a=340  nm, Wair=200  nm, and the number of air grooves N=10.

Fig. 2. (a) Sketch of 2D slot Bragg gating structure with a defect size of Wd in the 2D-FDTD simulations. The period of grating a and the width of air groove Wair is denoted in the figure. (b) Normalized transmission of 2D slot Bragg grating structure with a symmetric F-P cavity with the parameters of a=370  nm, Wair=260  nm, Wd=290  nm, and number of air grooves on each side of defect N=5.

Fig. 3. E-field amplitude distribution of Ez component along the Bragg grating structures [the black lines show the contour of the structures with the same parameters as in Fig. 2(b)] with excitation wavelength at (a) resonance peak wavelength of 1556 nm, (b) off-resonance wavelength of 1650 nm.

Fig. 4. (a) Sketch of 3D simulated structure. (b) Zero-order normalized transmission of 3D slot Bragg grating structure with different numbers of air grooves on each side of the F-P cavity.

Fig. 5. 3D-FDTD simulated zero-order normalized transmission with structure parameters as a=380  nm, Wair=260  nm, H=500  nm, Wsi=200  nm, Ws=100  nm, number of air grooves on each side of defect N=7 and varying defect size Wd.

Fig. 6. 3D-FDTD zero-order normalized transmission of slot Bragg grating structure with parameters of a=380  nm, Wair=260  nm, Wsi=200  nm, Ws=100  nm and the number of air grooves on each side of defect N=7 and with (a) slot etching depth H=400  nm while varying Wd=340, 360 and 380 nm. (b) Slot etching depth H=700  nm while varying Wd=320, 340, 360, and 400 nm.

Fig. 7. (a) Sketch of Bragg grating with silicon height larger than LN slot height. The air grooves etching depth equal to Hsi. (b) 3D-FDTD simulated zero-order normalized transmission with structure parameters as a=380  nm, Wair=260  nm, H=500  nm, Wsi=200  nm, Ws=100  nm, number of air grooves on each side of defect N=7, Wd=380  nm, and varying the silicon height Hsi.

Fig. 8. (a) 3D FDTD normalized transmission calculated by Poynting energy flux at the output of the WG with parameters of H=700  nm, a=380  nm, Wair=260  nm, Wd=340  nm, number of air grooves N=7 and with different Δn values of the LN. (b) λres versus different Δn deduced from (a).