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

在接近硅双光子带边缘（2.1um）的波长处，量子信息处理应用受益于许多理想的特性。在这里，硅表现出最小的双光子吸收率和最大的非线性折射，使这个波段成为低损耗非线性硅光子学的理想选择。具体来说，这些特性在利用自发四波混频（SFWM）设计光子对源时是需要的。光子对源在计算、通信和传感等领域是许多量子技术的基础，因此开发明亮、高纯度、难以区分和高预示效率的光子源至关重要。基于SFWM的光源由强泵浦激光提供动力，随后必须将其与单光子产品分离，并且需要将其抑制到单光子水平（-130dB）。这个项目将从上到下解决这个问题——提高SFWM源的效率，从下到下——提高泵阻过滤器的性能。将探索利用光子晶体腔作为光子对源，以较低的泵浦功率产生高质量的光子。这些源设计将与用于泵抑制的高消光比滤波器、集成片上滤波器和黑体背景片上滤波器的新思想相结合。这些过滤器在本质上是光谱和空间的。这些发展将开启新的应用，依赖于在硅芯片上集成预示光子对源。

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.