Fig. 1. Polarization independent DC waveguides based on SWG structure^[18-19]. (a) Structure in Ref. [18]; (b) structure in Ref. [19]

Fig. 2. Diagrams of SWG structure and equivalent uniform refractive index medium. (a) Diagram of SWG structure; (b) diagram of equivalent uniform refractive index medium

Fig. 3. Configuration of DC demultiplexer structure (inset is section view of coupled zone waveguide)

Fig. 4. L_c as a function of n(SiN_x) when g is 120 nm and160 nm. (a) g=120 nm; (b) g=160 nm

Fig. 5. g as a function of n(SiN_x) when demultiplexer is polarization-independent

Fig. 6. L_c and R of 1550 nm and 1310 nm optical signals as functions of g when demultiplexer is polarization-independent, and L as a function of R when m is less than 7. (a) L_c as a function of g; (b) R as a function of g; (c) L as a function of R

Fig. 7. LILand CT as functions of L. (a) LIL; (b) CT

Fig. 8. L¯IL and C¯T as functions of W_s and L_s. (a) L¯IL; (b) C¯T

Fig. 9. Field distributions of DC polarization-independent demultiplexer. (a) 1310 nm, TE polarization mode; (b) 1310 nm, TM polarization mode; (c) 1550 nm, TE polarization mode; (d) 1550 nm, TM polarization mode

Fig. 10. Normalized output power and CT for port2 and port3 as functions wavelength. (a) 1310 nm band, normalized output power; (b) 1550 nm band, normalized output power; (c) 1310 nm band, CT; (d) 1550 nm band, CT

Fig. 11. LIL and CT as functions of Δh, ΔW, Δg,and Δn(SiN_x). (a) Δh; (b) ΔW; (c) Δg; (d) Δn(SiN_x)