Fig. 7. Optical transitions.

a Scanning electron microscope (SEM) image of an optical transition from the oxide clad region to the cavity where the back end of line stack and the buried oxide have been removed using the developed wafer level postprocessing on the standard silicon photonic platform (iSiPP50G) chip. b Plot showing the spread of the experimentally extracted insertion loss values over the measured wavelength range for different core widths of the shallow etch waveguide-based optical transitions. The box extends from the lower to upper quartile values, the red dotted line represents the mean, and the light green line indicates the median. The inset shows a 3-d representation of the optimized optical transition