Efficient Silicon Nitride Quantum Interconnect for Intrinsic Silicon Nitride Single-Photon Emitters

Scalable on-chip quantum photonics requires efficient quantum interconnects between deterministic single-photon sources and low-loss waveguides. The discovery of intrinsic, nonstoichiometric nitrogen-rich silicon nitride (SiN) emitters provides a promising route for monolithic integration, enabling both enhanced emission rates and high extraction efficiencies. Here, we present a topology-optimized hybrid photonic-plasmonic quantum interconnect that functions as a cavity and coupler; it simultaneously enhances spontaneous emission and directs photons into a waveguide. By combining an Au nanodisk for Purcell enhancement with an inverse-designed SiN routing structure, we increase the emission rate while maintaining a coupling efficiency of ~79% (corresponding to a coupling loss of ~1.02 dB). These co-optimized plasmonic and dielectric components play complementary roles, enabling superior total collected photon power compared to dielectric-only designs. Native integration of single-photon sources in our design enables a robust quantum interconnect with the critical material uniformity across different functional elements and demonstrates a fabrication-aware, scalable approach to addressing key efficiency bottlenecks in large-scale quantum architectures.