ITR - Integrated Source of High-fidelity Entangled States for Quantum Information Processing

量子物理中的Sergienko纠缠研究得益于通过自发参数下转换(SPDC)的非线性光学过程产生的光子对的使用。应用包括分布式成像、计量学、密码学和计算。将量子密码学集成到现实世界的电信网络中，并使量子光学计算处理器具有可扩展性，可以通过减小其尺寸和开发高质量纠缠光子态的集成来源来促进。在共线同传结构的周期极化非线性光波导中的几个初步实现显示了几个优点。光子对的产生速度和单模光纤的耦合效率都得到了显著的提高。然而，产生的光子通常在时间上是关联的，但不是纠缠的。此外，频谱带宽也相当大。这就阻碍了它们在通信环境中的应用，因为这些态非常容易受到色散和偏振模色散的影响。本研究旨在通过开发一种新型的高保真纠缠光子源来克服这些问题。该方法利用周期极化非线性光波导中的反向传输准相位匹配。利用横向泵浦和第二类非线性相互作用，可以产生偏振纠缠光子对，这些光子对对称地从非线性波导的两端出射，准备耦合到单模光纤中。在这种结构中产生的光子的光谱带宽减少了一个数量级以上，从而允许色散不敏感的量子通信。通过将量子技术整合到现有的电信系统结构中，使用集成的高保真纠缠光子源将提高现实世界中可扩展的网络性能。这种设备的开发将为在芯片上创造密集的纠缠源和基本的量子光学计算门开辟一条道路。这反过来将加速第一台紧凑型量子光学计算机的出现。这个项目将为学生提供独特的多学科经验，应用尖端量子光学技术解决现代光学和电信中的广泛问题。研究里程碑。I)研究物理效应和设计特殊几何结构，导致产生频率和偏振纠缠的量子态；ii)利用周期极化的非线性波导中的反向传播相互作用产生高强度窄带宽偏振纠缠态的微型光源；iii)使用新的光源在电信波长上展示量子密码学和纠缠交换的增强性能。

0312556SergienkoEntanglement studies in quantum physics have benefited greatly from the use of photon pairs generated via the nonlinear optical process of spontaneous parametric down-conversion (SPDC). Applications include distributed imaging, metrology, cryptography, and computing. The integration of quantum cryptography into real-world telecommunications networks, and making quantum-optical computing processors scalable, can be fostered by reducing their size and developing an integrated source of high-quality entangled photon states. A few initial implementations of SPDC in periodically-poled nonlinear waveguides in the collinear copropagating configuration have demonstrated several advantages. Both the rate of photon-pair production and the single-mode fiber coupling efficiency are increased substantially. However, the generated photons are usually correlated in time but not entangled. Moreover, the spectral bandwidth is also rather large. This precludes their use in a telecommunication environment where such states are highly susceptible to chromatic and polarization-mode dispersion.This research aims at overcoming these problems by developing a novel integrated source of high-fidelity entangled photons. The new approach makes use of counterpropagating quasi-phase matching in periodically poled nonlinear waveguides. The use of transverse pumping, and of a type-II nonlinear interaction, allows the production of polarization-entangled photon pairs that exit symmetrically from opposite sides of a nonlinear waveguide, ready for coupling into single-mode optical fiber. The spectral bandwidth of the photons generated in this configuration is reduced by more than an order of magnitude, thereby allowing dispersion-insensitive quantum communications.Intellectual merit. The use of an integrated source of high-fidelity entangled photons will enhance real-world scalable network performance by incorporating quantum technology into the existing fabric of telecommunication systems. The development of such a device will open a path toward the creation of a dense population of entangled sources and elementary quantum-optical computing gates on a chip. This, in turn, will hasten the appearance of the first compact quantum-optical computers.Broader Impact. This program will provide students with unique multidisciplinary experiences in the application of cutting-edge quantum-optical techniques to a broad range of problems in modern optics and telecommunications.Research milestones. i) investigation of physical effects and design specific geometries leading to generation of quantum states entangled both in frequency and in polarization; ii) production of miniature sources of high-intensity narrow bandwidth polarization-entangled states using a counterpropagating interaction inside the periodically poled nonlinear waveguide; iii) demonstration of enhanced performance of quantum cryptography and entanglement swapping at telecommunication wavelengths using new source.