Vertical adiabatic transition between a silica planar waveguide and an electro-optic polymer fabricated with gray-scale lithography.

We report on a vertical adiabatic transition between silica planar waveguides and electro-optic (EO) polymer. Gray-scale lithography was used to pattern a polymer transition with an exponential profile. Excess losses of the order of 1 dB were measured, and good mode matching to simulation was observed. This configuration, which married the advantages of both silica and EO-polymer planar-optic technologies, demonstrates a new technique for fabricating hybrid active devices with high modulation speed, low insertion loss, and complex geometries.