We present the development, characterization, and evaluation of a modular, plug-and-play fiber-based entangled-photon source architecture for scalable industrial quantum networks. The design enables flexible integration and straightforward expansion within complex photonic infrastructures. Light collection is achieved using commercially available 780HP optical fibers coupled to monolithic microlenses and GaAs quantum dots, providing efficient photon extraction together with strong mechanical stability for reliable long-term operation. Combined with an optimized detection system, the source achieves a detected photon count rate of 2.13±0.03 MHz across four superconducting nanowire single-photon detector (SNSPD) channels and a peak entanglement fidelity of 97.0(3)% within an 8-ps temporal window. Comparative measurements using different optical configurations show only minor fidelity deviations of approximately 2%, demonstrating the robustness and reproducibility of the architecture. These results demonstrate the suitability of the proposed platform for scalable and deployable quantum communication systems.
Y. G. Zena, A. Rahimi, M. Langer et al.· Photonics for Quantum· 0 citations
As quantum key distribution (QKD) progresses from laboratory demonstrations toward practical deployment, quantum communi- cation networks increasingly require higher key rates and the ability to distribute independent secret keys among multiple users and network nodes. In this paper we present a promsing approach with multi-plane light conversion (MPLC) for demultiplexing entangled photons, transmitted through a few-mode fiber (FMF). We experimentally demonstrated a spatially multiplexed BBM92 QKD scheme. The modes are selectively excited through separate single-mode-fibers and subsequently separated by MPLC into distinct output ports. Unlike high-dimensional QKD based on coherent modal superpositions, our approach exploits distinguishable guided modes as parallel channels while preserving the entanglement required for QKD. For the multiplexed links, we obtain quantum bit error rates of $1.9 \pm 0.4\%$ for the channel 1 and $6.8 \pm 0.8\%$ for the channel 2. These results are relevant for scalable quantum-secured networks, space-division-multiplexed QKD systems, multi-user entanglement distribution, and future quantum internet architectures, where parallel quantum channels must be implemented without compromising the quantum correlations required for security.
Qian Zhang, Stefan Krause, Felix Kunzmann et al.· 0 citations