Experimental Characterization of Optical Switching Impairments in Hybrid Quantum-Classical Networks

This paper presents an experimental evaluation of the impact of optical switching equipment on the integrity of sensitive quantum signals, which are fundamental components of quantum networks. Focusing on switching in a Quantum Key Distribution (QKD) network as one example of a quantum network scenario, this study highlights how the impairments introduced by optical switches can significantly degrade the quality of quantum signals, resulting in a noticeable increase in the Quantum Bit Error Rate (QBER). This signal degradation poses serious challenges to the reliability and efficiency of the quantum networks. However, by accurately modeling the effects of switching-induced impairments, designing and implementing an ideal digital twin becomes feasible, which can cut QBER by up to 90% by identifying and addressing root causes and enabling proactive measures. Hybrid quantum-classical networks can benefit from such digital twins through improved quality and scalability.