基于轨道角动量编码的机载MDI-QKD系统性能分析方法研究

Performance Analysis of Airborne MDI-QKD Based on Orbital Angular Momentum Encoding

针对地面光纤和卫星量子网络存在传输距离和工作时间上的限制,提出了一种以无人机(UAVs)为中继平台,基于光子轨道角动量(OAM)编码的测量设备无关量子密钥分发(MDI-QKD)协议。利用无人机的机动性和可控性,建立了一条理论上安全的快速链路,采用光子OAM编码方式提高了信道鲁棒性。通过分析考虑涡旋光束扩展和无人机抖动等因素,发现传输距离会受到模式依赖衍射(SDD)和指向误差的影响,进而影响密钥率。研究结果表明,衍射效应在系统性能中起着主导作用,综合考虑SDD和无人机的抖动情况,传输距离的缩短程度可达58%,远超仅考虑大气湍流散射影响时的效果,这为基于无人机中继的量子密钥分配系统建立了理论模型。所提工作提升了理论分析的完备性,缩小了理论分析与实验验证之间的距离,为未来无人机量子通信组网的发展提供了重要的理论参考。

To address the limitations of transmission distance and operational time in ground-based optical fiber and satellite quantum networks,a measurement-device-independent quantum-key-distribution(MDI-QKD)protocol based on photon orbital angular momentum(OAM)encoding with unmanned aerial vehicles(UAVs)as relay platforms is proposed.Leveraging the mobility and controllability of UAVs,a theoretically secure rapid link is established,and the channel robustness is enhanced using photon OAM encoding.By considering factors such as vortex beam expansion and UAV jitter in an analysis,the transmission distance is shown to be affected by state-dependent diffraction(SDD)and pointing errors,thus consequently affecting the key rate.Additionally,the research results indicate that diffraction effects contribute significantly to system performance.Considering both SDD and UAV jitter,the transmission distance can decrease by 58%,which significantly exceeds the effects observed when considering only atmospheric turbulence scattering.This result is used to establish a theoretical model for quantum-key-distribution systems based on UAV relay.This study enhances the comprehensiveness of theoretical analysis and reduces the discrepancy between theoretical analysis and experimental verification,thus providing an important theoretical reference for the development of future UAV-based quantum communication networks.