The ongoing development of powerful quantum computers will render our existing crypto primitives, based on mathematical complexities, vulnerable to attacks. Quantum Key Distribution (QKD) promises to provide a secure key exchange mechanism based on the law of nature, and this ensures security not only today but also in the future, even when the adversary is all-powerful. There have been multiple QKD point-to-point demonstrations worldwide, and our research team has also recently demonstrated Coherent One Way (CoW) and Differential Phase Shift (DPS) QKD protocols. This work focuses on the technical challenges of demonstrating QKD protocols (CoW and DPS) in the field and taking it further to establish a metropolitan QKD secure access network termed as "Metro Area Quantum Access Network" (MAQAN). We also plan to devise a key relay mechanism for MAQAN which shall be demonstrated in both Star and Mesh topology. It will pave the way for long-distance QKD in the future network expansion.


Considering the field deployment requirements, we plan to move our QKD implementations to Xilinx's Ultrascale+ architecture with a hardcore processor (PS) interfaced with the programming logic (PL). The control logic shall be implemented on PL side. The operational logic shall be implemented on the PS side through Python codes running over an embedded Linux environment. We plan to use a multiprocessing framework (OpenAMP) to assign individual cores for specific QKD operations like optics control, key distillation engine, software-defined network, and machine learning. Machine learning shall play an important role in improving the performance of quantum communication networks. We propose to design an ML Ecosystem in MAQAN in which a PS core shall be dedicated to logging important operational parameters and running various ML models, positively influencing the network operation. We shall use this ecosystem to demonstrate applications towards parameter optimization (DLI and IM stability), key formatting and storage management, QKD protocol selector, etc.