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

自发参量下转换（SPDC）的非线性光学过程所产生的光子对的使用极大地促进了量子物理中的纠缠研究。应用包括分布式成像、计量、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可扩展，可以通过减小其尺寸和开发高质量纠缠光子态的集成源来促进。在共线共传播结构的周期极化非线性波导中，SPDC的一些初步实现已经显示出一些优点。光子对的产生速率和单模光纤的耦合效率都大大提高。然而，产生的光子通常是时间相关的，而不是纠缠的。此外，光谱带宽也相当大。这就排除了它们在电信环境中的使用，因为这种状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集成源来克服这些问题。该方法利用了周期极化非线性波导中的反传播准相位匹配。利用横向泵浦和ii型非线性相互作用，可以产生偏振纠缠光子对，这些光子对从非线性波导的两侧对称地出口，准备耦合到单模光纤中。在这种配置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。知识价值。高保真纠缠光子集成源的使用将通过将量子技术整合到电信系统的现有结构中来增强现实世界可扩展网络的性能。这种装置的发展将为在芯片上创建密集的纠缠源和基本量子光学计算门开辟道路。反过来，这将加速第一台紧凑型量子光学计算机的出现。更广泛的影响。该项目将为学生提供独特的多学科经验，将前沿量子光学技术应用于现代光学和电信领域的广泛问题。研究的里程碑。I)研究物理效应和设计特定的几何形状，从而产生频率和偏振纠缠的量子态；Ii)利用周期极化非线性波导内部的反传播相互作用产生高强度窄带宽偏振纠缠态的微型源；Iii)使用新光源在电信波长上增强量子加密和纠缠交换性能的演示。

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.