3-D semivectorial analysis to calculate facet reflectivities of semiconductor optical waveguides based on the bi-directional method of line BPM (MoL-BPM)

Direct three-dimensional (3-D) calculation of the facet reflectivities to the air of semiconductor strip-loaded and buried optical waveguides is reported. The analytical procedure is based on the semivectorial bi-directional method of line BPM (MoL-BPM). The results indicate that widely utilized two-dimensional (2-D) analytical methods cannot be applied to semiconductor waveguides that have cores with small aspect ratios, and that strip-loaded and buried optical waveguides behave very differently as regards their ridge and core widths. The radiation losses at facet reflections are also clarified.