Larson Walker, Courtney Trevor L, Keyser Christian
Opt Express. 2022 Feb 14;30(4):5739-5757. doi: 10.1364/OE.446488.
Spectrally pure photons heralded from unentangled photon pair sources are crucial for any quantum optical system reliant on the multiplexing of heralded photons from independent sources. Generation of unentangled photon pairs in gas-filled hollow-core photonic crystal fibers specifically remains an attractive architecture for integration into quantum-optical fiber networks. The dispersion design offered by selection of fiber microstructures and gas pressure allows considerable control over the group-velocity profile which dictates the wavelengths of photon pairs that can be generated without spectral entanglement. Here, we expand on this design flexibility, which has previously been implemented for four-wave mixing, by modeling the use of a static, periodically poled electric field to achieve an effective quasi-phase-matched three-wave mixing nonlinearity that creates spontaneous parametric downconversion. Electric-field-induced quasi-phase-matched spontaneous parametric downconversion enables control of phase matching conditions that is independent of the group velocity, allowing phase matching at arbitrary wavelengths without affecting the entanglement of photons at those wavelengths. This decoupling of entanglement engineering and phase matching facilitates spectrally pure photon pair generation with efficiency and wavelength-tunability that is otherwise unprecedented.
对于任何依赖于来自独立源的 heralded 光子复用的量子光学系统而言，从非纠缠光子对源产生的光谱纯光子至关重要。特别是在充气空心光子晶体光纤中产生非纠缠光子对，仍然是集成到量子光纤网络的一种有吸引力的架构。通过选择光纤微结构和气压提供的色散设计，能够对群速度分布进行相当程度的控制，而群速度分布决定了可以产生而无光谱纠缠的光子对的波长。在此，我们通过对使用静态、周期性极化电场以实现有效准相位匹配的三波混频非线性（从而产生自发参量下转换）进行建模，扩展了这种先前已用于四波混频的设计灵活性。电场诱导的准相位匹配自发参量下转换能够控制与群速度无关的相位匹配条件，从而允许在任意波长处实现相位匹配，而不会影响这些波长处光子的纠缠。纠缠工程与相位匹配的这种解耦有助于以前所未有的效率和波长可调性产生光谱纯光子对。
