Different approaches for integrating HBTs and EAMs

We compare three different approaches to combine heterojunction bipolar transistors (HBTs) and electroabsorption waveguide modulators (EAMs) for building monolithically integrated opto-electronic circuits: A single stage HBT-driver is applied to an EAM load where the HBT layer stack is grown onto the EAM-layer structure. This is compared to a merged integration of HBTs and EAMs with the waveguide inside the transistor layers with separate devices, and a merged device called HBT-EAM. The compact layer structure and processing supports the concept of this merged device.