Efficient sources and strong filters for silicon quantum photonics in the mid-infrared

在硅的双光子带边（2.1um）附近的波长处，量子信息处理应用受益于许多期望的特性。在这里，硅在双光子吸收率中表现出最小值，在非线性折射中表现出最大值，这使得该频带对于低损耗非线性硅光子学是理想的。具体来说，这些特性是利用自发四波混频（SFWM）设计光子对源所需的。光子对源是计算、通信和传感等领域许多量子技术的基础，因此开发明亮、高纯度、不可分辨和高预示效率的光子源至关重要。基于SFWM的源由强泵浦激光器供电，该强泵浦激光器随后必须与单光子产物分离，需要抑制到单光子水平（-130dB）。这个项目将从上面解决这个问题，通过使SFWM源更有效，从下面解决这个问题，通过使泵抑制过滤器更好。将探索使用光子晶体腔作为光子对源，以相对低的泵浦功率产生高质量的光子。这些光源设计将与用于泵浦抑制的高消光比滤波器的新想法相结合，集成在片上，并与黑体背景的片上滤波相结合。这些滤波器在本质上是光谱和空间的。这些发展将打开新的应用依赖于集成的预示光子对源的硅芯片。

At wavelengths near the two-photon band edge of silicon (2.1um) quantum information processing applications benefit from many desirable properties. Here, silicon exhibits a minimum in the two-photon absorption rate and a maximum in the nonlinear refraction, making this band ideal for low-loss nonlinear silicon photonics. Specifically, these properties are desired in the design of photon pair sources utilising spontaneous four wave mixing (SFWM). Photon pair sources underpin many quantum technologies in computation, communications and sensing and so the development of bright, high purity, indistinguishable and high heralding efficiency photon sources is crucial. SFWM based sources are powered by an intense pump laser which must be subsequently separated from the single photon products, with suppression needed right down to the single photon level (-130dB). This project will attack this problem from above-by making SFWM sources more efficient-and from below-by making pump-rejection filters better. The use of photonic crystal cavities as photon-pair sources will be explored to produce high-quality photons with relatively low pump powers. These source designs will be combined with fresh ideas on high-extinction-ratio filters for pump rejection, integrated on-chip, and with on-chip filtering of blackbody background. These filters will be both spectral and spatial in nature. These developments will open new applications relying on the integration of heralded photon-pair sources on silicon chips.