Ge electroabsorption modulators and SiGe technology for optical interconnects

Ge/SiGe quantum well electroabsorption modulators grown on silicon through relaxed SiGe buffers had shown strong quantum-confined Stark effect (QCSE), even though Ge is an in-direct band gap semiconductor. The absorption characteristic near the direct band gap edge can be tuned by applying an electric field. QCSE is the most efficient optical modulation mechanism through direct light absorption and promising for reducing the device size and power consumption. The device fabrication here is based on Ge-rich SiGe technology, which is also commonly used for various silicon photonics applications. Here we will discuss Ge QCSE electroabsorption modulators as well as the consideration of SiGe process integration for optical interconnects.