Novel Electroabsorption Modulator Design Based on Coplanar Waveguide Configuration

We present a new design approach for electroabsorption modulators based on integrating a microwave element monolithically with the photonic element. A new method is reported for planarizing and patterning a low-permittivity film using a hydrogen silsesquioxane spin-on coating with electron beam exposure; after 5 coating steps, the layer thickness was 6 μm. We demonstrate the design by fabricating a coplanar waveguide with a 50 Ω characteristic impedance at the input port, at operating frequencies up to 67 GHz.