Compact Electroabsorption Modulators for Photonic Integrated Circuits, Using an Isolated Pedestal Contact Scheme

We demonstrate a shallow ridge waveguide, lumped element electroabsorption modulator (EAM) based on AlInGaAs multiple quantum wells, operating with input powers up to 8 dBm. The device was isolated between two DC controlled sections, using angled etched slots in the waveguide, minimizing optical feedback, while also providing 40-KΩ resistance between devices. The EAM uses a planar isolated pedestal contact with a benzocyclobutene bridge, allowing for a small contact footprint of just 0.024 mm², while being suitable for flip-chip packaging. The parasitic capacitance was measured to be 19.6 fF, and the EAM has a f_3dB bandwidth of 42 GHz.