A novel optimal design of sub-wavelength metal rectangular gratings for the polarizing beam splitter （PBS） is proposed. The method is based on effective medium theory and the method of designing single layer antiref...A novel optimal design of sub-wavelength metal rectangular gratings for the polarizing beam splitter （PBS） is proposed. The method is based on effective medium theory and the method of designing single layer antireflection coating. The polarization performance of PBS is discussed by rigorous couple-wave analysis （RCWA） method at a wavelength of 1550 nm. The result shows that sub-wavelength metal rectangular grating is characterized by a high reflectivity, like metal films for TE polarization, and high transmissivity, like dielectric films for TM polarization. The optimal design accords well with the results simulated by RCWA method.展开更多
The unconditional security of quantum key distribution(QKD) can be guaranteed by the nature of quantum physics.Compared with the traditional two-dimensional BB84 QKD protocol, high-dimensional quantum key distribution...The unconditional security of quantum key distribution(QKD) can be guaranteed by the nature of quantum physics.Compared with the traditional two-dimensional BB84 QKD protocol, high-dimensional quantum key distribution(HDQKD) can be applied to generate much more secret key.Nonetheless, practical imperfections in realistic systems can be exploited by the third party to eavesdrop the secret key.The practical beam splitter has a correlation with wavelength,where different wavelengths have different coupling ratios.Using this property, we propose a wavelength-dependent attack towards time-bin high-dimensional QKD system.What is more, we demonstrate that this attacking protocol can be applied to arbitrary d-dimensional QKD system, and higher-dimensional QKD system is more vulnerable to this attacking strategy.展开更多
讨论了一种用于DWDM系统中的光开关、偏振无关隔离器等单元器件中的微小薄膜型偏振分束器制造的关键技术。光学膜层采用数学多重优化设计方法;采用Monte Carlo允差分析原理分析膜层的容差,以便选择更易制备的膜系;计算膜层的M ac leod...讨论了一种用于DWDM系统中的光开关、偏振无关隔离器等单元器件中的微小薄膜型偏振分束器制造的关键技术。光学膜层采用数学多重优化设计方法;采用Monte Carlo允差分析原理分析膜层的容差,以便选择更易制备的膜系;计算膜层的M ac leod极值灵敏度,得到所选膜系各个膜层的误差要求;模拟光学监控过程,以制定相应的膜厚监控策略。设计了实用的棱镜胶合装置,得到了较高技术指标的PBS棱镜。结果表明,棱镜的光学冷加工,是器件制造的基础;光学薄膜的设计与制备是器件制造的关键,也是难点;棱镜的胶合是器件不可忽视的环节。展开更多
基金Project supported by Science Foundation of the Chongqing Committee of Education,China (Grant No KJ071205)
文摘A novel optimal design of sub-wavelength metal rectangular gratings for the polarizing beam splitter （PBS） is proposed. The method is based on effective medium theory and the method of designing single layer antireflection coating. The polarization performance of PBS is discussed by rigorous couple-wave analysis （RCWA） method at a wavelength of 1550 nm. The result shows that sub-wavelength metal rectangular grating is characterized by a high reflectivity, like metal films for TE polarization, and high transmissivity, like dielectric films for TM polarization. The optimal design accords well with the results simulated by RCWA method.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0302600)the National Natural Science Foundation of China(Grant No.61675235)
文摘The unconditional security of quantum key distribution(QKD) can be guaranteed by the nature of quantum physics.Compared with the traditional two-dimensional BB84 QKD protocol, high-dimensional quantum key distribution(HDQKD) can be applied to generate much more secret key.Nonetheless, practical imperfections in realistic systems can be exploited by the third party to eavesdrop the secret key.The practical beam splitter has a correlation with wavelength,where different wavelengths have different coupling ratios.Using this property, we propose a wavelength-dependent attack towards time-bin high-dimensional QKD system.What is more, we demonstrate that this attacking protocol can be applied to arbitrary d-dimensional QKD system, and higher-dimensional QKD system is more vulnerable to this attacking strategy.
文摘讨论了一种用于DWDM系统中的光开关、偏振无关隔离器等单元器件中的微小薄膜型偏振分束器制造的关键技术。光学膜层采用数学多重优化设计方法;采用Monte Carlo允差分析原理分析膜层的容差,以便选择更易制备的膜系;计算膜层的M ac leod极值灵敏度,得到所选膜系各个膜层的误差要求;模拟光学监控过程,以制定相应的膜厚监控策略。设计了实用的棱镜胶合装置,得到了较高技术指标的PBS棱镜。结果表明,棱镜的光学冷加工,是器件制造的基础;光学薄膜的设计与制备是器件制造的关键,也是难点;棱镜的胶合是器件不可忽视的环节。
