Design of Polarization-Independent Coarse Wavelength Splitters Based on Ridge-Waveguide Directional Couplers

Table 1

Refractive index of Si_0.9Ge_0.1 and Si materials for TE and TM modes of 𝜆=1.31 μm and 1.55 μm.

Material	λ = 1.31 μm		λ = 1.55 μm
	TE	TM	TE	TM
Si	3.508	3.508	3.476	3.476
Si0.9Ge0.1	3.5395	3.5478	3.5065	3.5163