Experiment studies of decoy state BB84 QKD using optical-switch-based polarization multiplexing

De Wei Liao^1*, Yuan-Ren Yeh¹, Yu-Han Hung^1,2

¹Department of Photonics, National Sun Yat-sen University, Kaohsiung, Taiwan
²Miniaturized Photonic Gyroscope Research Center, National Sun Yat-sen University, Kaohsiung, Taiwan

* Presenter:De Wei Liao, email:david881004@gmail.com

Our research focuses on utilizing optical switches to enhance the key rate of Decoy State BB84 Quantum key distribution (QKD) systems. We conducted a simulated optical switch experiment using Python productivity for Zynq (PYNQ), a coupler, and a Variable Optical Attenuator (VOA) to confirm the feasibility of our idea. Precise polarization state switching was demonstrated. Our experimental results clearly distinguish between different decoy states (including signal, weak, and vacuum) and polarization states (0 degrees and 90 degrees). The transmission repetition rate can reach up to 2 kHz. This experiment validates the feasibility of our idea. Since many inspiring optical switches design have been proposed and demonstrated to achieveattosecond(as) switching speeds, the objective of this study is to propose a novel idea to enhance the secure key rate through optical-switch-based polarization multiplexing.

Keywords: Decoy State BB84, Optical Switch, Quantum Key Distribution, PYNQ