Effect and Compensation of Polarization‐Dependent Loss in Free‐Space Reference Frame Independent Quantum Key Distribution
Kyongchun Lim, Byung‐Seok Choi, Ju Hee Baek, Minchul Kim, Joong‐Seon Choe, Kap‐Joong Kim, Dong Churl Kim, Junsang Oh, Chun Ju Youn · Advanced Quantum Technologies · 2024
Abstract Polarization‐dependent loss (PDL) poses a critical challenge in implementing free‐space quantum key distribution (QKD) systems. This study investigated the theoretical and experimental impact of PDL on polarization‐encoded qubits and experimentally demonstrated a method to mitigate these effects. The proposed compensation method could effectively restore the integrity of polarization states, enhancing the robustness and security of QKD systems. Specifically, a secret key rate of 94.01% could be recovered with 5 dB PDL. This study contributes to advancing scalable and secure quantum communication technologies by addressing the critical issue of PDL in QKD systems.