Scalable design of single-photon emitters integrated on silicon with a crossed-waveguide architecture

Abstract

The scalable integration of deterministic telecom-band single-photon sources into silicon photonic circuits is a critical challenge for quantum information processing, primarily bottlenecked by the stringent alignment tolerances of conventional hybrid coupling schemes. To overcome this limitation, we propose and numerically demonstrate a highly efficient, alignment-tolerant hybrid architecture integrating an InAs/InP quantum dot (QD) onto a Si waveguide. Our design leverages a one-dimensional photonic crystal nanobeam cavity that seamlessly funnels QD emission into an InP waveguide without out-of-plane scattering, combined with a crossed-waveguide geometry for robust phase-matched mode transfer into the underlying Si circuit. By systematically optimizing the three-stage coupling process—emitter-to-cavity, cavity-to-waveguide, and waveguide-to-waveguide—we achieve a near-unity theoretical coupling efficiency of 99.7\%. Full-system dipole simulations confirm a total transfer efficiency of 97\%, alongside broad angular ($\pm 1.5^\circ$) and spatial placement tolerances that are highly compatible with practical micro-transfer printing techniques. Furthermore, by eliminating the need for complex mode expanders, our architecture ensures an ultra-compact footprint. This wavelength- and material-agnostic modular framework offers a manufacturable, universal pathway for the large-scale integration and mass production of diverse solid-state quantum emitters in dense photonic networks.