Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 47: Focus Session: Quantum Technologies in Deployed Systems II

HL 47.7: Talk

Thursday, March 20, 2025, 12:15–12:30, H17

Establishing a Quantum Local Area Network in Berlin City using Deterministic Quantum Light Sources — •Martin von Helversen¹, Lucas Rickert¹, Anne Rohwäder¹, Kinga Zolnacz², Koray Kaymazlar¹, Daniel Vajner¹, Anna Musial³, Grzegorz Sek³, Hanqing Liu⁴, Zhichuan Niu⁴, and Tobias Heindel¹ — ¹Institute of Solid State Physics, Technical University Berlin, Berlin, Germany — ²Department of Optics and Photonics, Wroclaw University of Science and Technology, Wroclaw, Poland — ³Department of Experimental Physics, Wroclaw University of Science and Technology, Wroclaw, Poland — ⁴Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China

Applications of quantum information enabled by solid-state quantum light sources currently witness the transition from laboratory proof-of-concept to field-experiments. In this contribution we present our recent progress in establishing a quantum local area network at the Campus Charlottenburg of TU Berlin. We show results of an actively stabilized free-space optical link with an effective length of 400 m and an end-to-end transmission of >70%. In addition, we operate a fiber-link between two buildings consisting of 6x 650 m of dark optical fiber. Moreover, we discuss the deployment of mobile deterministic single-photon sources based on compact cryocoolers and fiber-pigtailed quantum dot microcavities [FC-CBG] and evaluate the suitability for implementations of different types of cryptographic primitives. [1] Rickert, Lucas, et al., arXiv:2409.08982 (2024) [2] Rickert, Lucas, et al., arXiv:2408.02543 (2024).

Keywords: semiconductor quantum dots; plug-and-play; quantum-key-distribution; FSO; field-test