Fig. 1. Structural diagram of two-dimensional photonic crystal waveguide heterostructure, and refractive index distribution of substrate material along x-direction position. (a) Structural diagram of two-dimensional photonic crystal waveguide heterostructure; (b) refractive index distribution of substrate material along x-direction position

Fig. 2. TE and TM energy band diagrams of PhC1 and PhC2, and photonic bandgaps of TE and TM modes of PhC1(PhC2) varying with r₁(r₂). (a) TE and TM energy band diagrams of PhC1; (b) TE and TM energy band diagrams of PhC2; (c) photonic bandgaps of TE and TM modes of PhC1 varying with r₁; (d) photonic bandgaps of TE and TM modes of PhC2 varying with r₂

Fig. 3. Transmittance of TE, TM, and CPL in PhC1 and PhC2 as a function of width of waveguide. (a)-(c) Transmittance of TE, TM, and CPL in PhC1 as a function of d₁ for step of 20 nm; (d)-(f) transmittance of TE, TM, and CPL at 1550 nm in PhC1 for different d₁; (g)-(i) transmittance of TE, TM, and CPL in PhC2 as a function of d₂ for step of 20 nm; (j)-(l) transmittance of TE, TM, and CPL at 1550 nm in PhC2 for different d₂

Fig. 4. Forward and backward incident electric field intensity distributions at 1550 nm of heterostructure after removing 6×3 air holes on right side of PhC2. (a) TE, forward; (b) TM, forward; (c) CPL, forward; (d) TE, backward; (e) TM, backward; (f) CPL, backward; transmittance spectra of studied waveband of (g) TE, (h) TM, and (i) CPL

Fig. 5. Electric field intensity, polarization, and phase distributions of CPL in y-z plane of 2D PhC heterostructure, transmittance and transmittance contrast of CPL in 2D PhC heterostructure, and forward transmittance of CPL in 2D PhC structure and finite thickness PhC heterostructure slab based on silica substrate. (a) Electric field intensity,polarization distribution, and (b) phase distribution of CPL in y-z plane of 2D PhC heterostructure; (c) transmittance and transmittance contrast of CPL in 2D PhC heterostructure; (d) forward transmittance of CPL in 2D PhC structure and finite thickness PhC heterostructure slab based on silica substrate