Ultra-fast photonic chips bring scalable quantum computers closer

German researchers at Julius Maximilian University of Würzburg have developed an ultra-fast, ultra-low-loss optical phase modulator by integrating ferroelectric barium titanate (BTO) with III-V photonics on a single chip platform. This innovation addresses a critical challenge in quantum computing: precisely controlling quantum light signals without destroying their fragile quantum information. The team grew their own high-purity BTO crystals using molecular beam epitaxy to maintain the necessary ferroelectric properties, enabling the modulator to operate at extremely high speeds with minimal optical losses. Funded by the German Federal Ministry of Research, Technology, and Space, this breakthrough could accelerate the transition of quantum photonics from experimental setups to scalable, practical quantum technologies. Beyond the phase modulator, the researchers are developing a comprehensive toolkit for photonic quantum circuits, including waveguides, couplers, and integrated quantum light sources. Their modular approach, likened to assembling Lego bricks, allows for rapid design, fabrication, and testing of quantum circuits