High-speed and high-performance polarization-based quantum key distribution system without side channel effects caused by multiple lasers

摘要

Side channel effects such as temporal disparity and intensity fluctuation ofphoton pulses caused by random bit generation with multiple laser diodes inhigh-speed polarization-based BB84 quantum key distribution (QKD) systems canbe eliminated by increasing DC bias current condition. However, backgroundphotons caused by the spontaneous emission process under high DC bias currentdegrade the performance of the QKD systems. In this study, we investigated, forthe first time, the effects of spontaneously emitted photons on the systemperformance in a high-speed QKD system at a clock rate of 400 MHz. Also, wefurther show improvements of system performance without side channel effects byutilizing temporal filtering technique with real-time FPGA signal processing.