2025/06/23 by Ponosova, Anastasiya, Zhluktova, Irina, Ruzhitskaya, Daria +6 · 1 citation
#FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2506.19091
Quantum key distribution systems offer cryptographic security, provided that all their components are thoroughly characterised. However, certain components might be vulnerable to a laser-damage attack, particularly when attacked at previously untested laser parameters. Here, we show that exposing 1550-nm fiber-optic isolators to 1061-nm sub-nanosecond pulsed illumination with 1.16 W average power permanently degrades their isolation at 1550 nm, while their forward transparency is less affected. One experimental sample was exposed to 17-mW average power picosecond attacking pulses that temporarily reduced its isolation below the specified guaranteed minimum value. This indicates a potential security threat in these attacking laser regimes that need to be addressed by improving security analysis for various light-injection attacks.