With high integration density and excellent optical properties, silicon photonics is becoming a promising platform for complete integration and large-scale optical quantum information processing. Scalable quantum information applications need photon generation and detection to be integrated on the same chip, and we have seen that various devices on the silicon photonic chip have been developed for this goal. This paper reviews the relevant research results and state-of-the-art technologies on the silicon photonic chip for scalable quantum applications. Despite the shortcomings, the properties of some components have already met the requirements for further expansion. Furthermore, we point out the challenges ahead and future research directions for on-chip scalable quantum information applications.

The continuous-time quantum walk (CTQW) is the quantum analogue of the continuous-time classical walk and is widely used in universal quantum computations. Here, taking the advantages of the waveguide arrays, we implement large-scale CTQWs on chips. We couple the single-photon source into the middle port of the waveguide arrays and measure the emergent photon number distributions by utilizing the fiber coupling platform. Subsequently, we simulate the photon number distributions of the waveguide arrays by considering the boundary conditions. The boundary conditions are quite necessary in solving the problems of quantum mazes.

Higher emission rates and controllable emission direction are big concerns when it comes to finding a good single photon source. Recently, surface plasmons are introduced to this application, as they can manipulate and enhance the luminescence of single emitters. Here, we experimentally achieve a wide-area multiple directional enhanced light source through periodic metal grating structures. The surface-plasmon-coupled emission can have multiple precisely emission angles by just changing the period of the grating. Our result indicates that metal plasmonic grating can be used as a productive quantum device for unidirectional quantum light sources in quantum optics.