Technische Universität Berlin Develops New Architecture to Fabricate 36-Quantum Light Source Chip

en.Wedoany.com Reported - Technische Universität Berlin (TU Berlin), in collaboration with the University of Oldenburg, has developed a novel chip architecture that determines the position of quantum dots directly during crystal growth, enabling the fabrication of scalable quantum chips containing multiple identical light sources.

The research team is led by Professor Stephan Reitzenstein. In traditional methods, quantum dots capable of generating single light particles form randomly during material growth, requiring laborious selection processes when multiple identical sources are needed. The new method uses a special chip layer called a "stressor" to generate precise stress in the material, guiding quantum dots to grow at desired locations.

Subsequently, the team directly integrated the quantum dots into ring resonators for efficient collection of the generated light. The entire process is completed using standard lithography techniques, without the need for pre-positioning quantum dots. Using this method, the team fabricated an array of 36 quantum light sources, all of which are fully functional. The best-performing device successfully coupled nearly half of the generated light particles out of the chip. The quantum mechanical purity of individual light particles exceeds 99%, and the generated photons exhibit highly consistent characteristics, which is crucial for applications such as quantum networks that require precise interactions among a large number of photons.

Optical quantum chips are considered key components for secure quantum communication, quantum networks, quantum sensing, and photonic quantum computers. This method aims to help research institutions and industry transition from individual laboratory demonstrations to scalable, technologically viable platforms. The research team also incorporated simulations from the research group of Christopher Gies at the University of Oldenburg to analyze the impact of minor deviations in quantum dot positioning on device performance. The insights gained will guide the design of next-generation quantum chips. The research results have been published in the professional journal Light: Science and Applications.