685326.fig.0012a
(a) Modal propagation velocity as a function of scan angle for the fundamental quasi-symmetric mode of a ridge in Si with   ×  frequency = 700
685326.fig.0012b
(b) Modal propagation velocity as a function of scan angle for the fundamental quasi-antisymmetric mode of a ridge in Si with   ×  frequency = 700
Figure 12: Mode behavior for the fundamental (a) quasisymmetric ( ) and (b) quasi-antisymmetric ( ) ridge modes as a function of scan angle between planes of mirror symmetry for different Silicon wafers. Variations in velocity are quite subtle, suggesting that anisotropy may not be a significant issue while designing ridge waveguides in Silicon.