A Directly Modulated Laser Platform for High-Dimensional Quantum Key Distribution

Quantum Physics [Submitted on 13 Mar 2026] A Directly Modulated Laser Platform for High-Dimensional Quantum Key Distribution Yang Zhou, Xing-Yu Zhou, Shu-Fan Wu, Qiang Zeng, Zhi-Liang Yuan, Qin Wang High-dimensional quantum key distribution (HD-QKD) offers a promising approach to enhance secret key rates beyond conventional binary-encoded QKD, addressing the growing demand for secure data transmission. However, the practical application of most HD-QKD systems has been hindered by their complexity, as they require the preparation and detection of quantum states in large Hilbert spaces. Here, we design and experimentally realize a directly modulated laser platform for HD-QKD. It operates at a repetition rate of 312.5 MHz, yielding a remarkably simple and scalable architecture. Through which, we achieve a record transmission distance of 250 km for HD-QKD, demonstrating its feasibility for long-distance quantum communication. Furthermore, we witness that the four-dimensional states outperform their two-dimensional counterpart in secret key rate, highlighting the practical advantage of high-dimensional encoding. This simple and scalable approach shows strong potential for chip-scale integration. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2603.12819 [quant-ph]   (or arXiv:2603.12819v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2603.12819 Focus to learn more Submission history From: Qin Wang [view email] [v1] Fri, 13 Mar 2026 09:20:29 UTC (9,102 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-03 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)