Silicon-based photonics is currently considered the next generation photonics platform for embedded communications. However, the development of compact and low power optical modulators remains a challenge. Here we report a giant electro-optical effect in Ge/SiGe coupled quantum wells. This promising effect is based on the anomalous quantum Stark effect due to the separate confinement of electrons and holes in coupled Ge/SiGe quantum wells. This phenomenon can be used to significantly improve the performance of light modulators compared to the standard approaches developed so far in silicon photonics. We have measured changes in the refractive index up to 2.3 × 10-3 at a bias voltage of 1.5 V with a corresponding modulation efficiency VπLπ of 0.046 Vcm. This demonstration paves the way for the development of efficient high-speed phase modulators based on Ge/SiGe material systems.
Post time: Jun-06-2023