PIC based Implementation of DPS-QKD Transceiver

Photonic integrated circuits (PICs) provide several key benefits such as compact size, improved robustness, scalable manufacturing potential, and the capability for very fast operation. Despite advancements, the application of Photonic Integrated Circuits (PICs) for Differential Phase Shift QKD (DPS-QKD) remains relatively underexplored. DPS-QKD offers simplicity, high key generation efficiency, and resilience against photon-number splitting attacks, making it a promising quantum cryptography protocol. This work presents the working model of DPS-QKD using Lumerical interconnect, which is optimized for PIC design. Furthermore, we have carried out an analytical evaluation of the proposed PIC design based on the achievable QBER and the corresponding secured key rate. Our findings indicate that a secured DPS - QKD link can be achieved for a 200 km fiber length achieving 3.07% QBER and 1.8 Kbps secured key rate.