Chip-based measurement-device-independent quantum key distribution in the presence of polarization-dependent loss
Phys. Rev. A 113, 042454 – Published 27 April, 2026
DOI: https://doi.org/10.1103/43w2-pb8n
Abstract
Quantum key distribution (QKD) is a crucial solution for future secure communications because it provides information-theoretic security based on the principles of quantum mechanics. However, in practical polarization-encoded QKD systems, due to physical structural limitations, practical modulators inevitably introduce polarization-dependent loss (PDL), which can undermine the security of the generated keys. In this work, we propose and experimentally demonstrate a polarization-encoded measurement-device-independent QKD (MDI-QKD) system based on two silicon-on-insulator (SOI) chips, and explicitly quantify the impact of PDL in key rate estimation. We successfully extend the transmission distance to 202 km, which fully validates the feasibility of the polarization-loss-tolerant method. This work provides essential technical support for the deployment of low-cost, high-security integrated optical quantum networks with imperfect practical devices.
