Fig. 1. The proposed LNOI-based waveguide mode converter using V-shaped silicon. (a) Schematic; (b) top and side view

Fig. 2. Device performance dependent on the deviation distance y of the array. (a) Mode conversion efficiency; (b) mode crosstalk; (c) insertion loss

Fig. 3. Device performance dependent on the period number N and period T of the V-shaped silicon.（a）N=18；（b）N=14；（c）N=16；（d）N=20；（e）N=22；（f）N=24

Fig. 4. Width w and sag length d of the V-shaped silicon affecting on the device performance.（a）d=0.8 μm；（b）d=0.4 μm；（c）d=0.6 μm；（d）d=1 μm；（e）d=1.2 μm；（f）d=1 μm，w=400 nm

Fig. 5. Device performance dependent on the thickness h of the silicon array.（a）h=100 nm；（b）h =150 nm；（c）h=200 nm；（d）h=250 nm；（e）h=300 nm；（f）h=250 nm，T=500 nm

Fig. 6. The improvement effect of period T on device performance. (a) Mode conversion efficiency; (b) bandwidth analysis

Fig. 7. Electric field evolution of the proposed TFLN waveguide based TE₀-to-TE₁ mode converter

Fig. 8. Device performance dependent on key dimensions. (a) Sag length d;(b) width w; (c) thickness h

Fig. 9. Electric field evolution of the proposed TFLN waveguide based TE₀-to-TE₂ mode converter