On-chip integration of site controlled hBN quantum emitters in a low-emission silicon nitride platform

Single-photon emitters hosted by atomically thin two-dimensional (2D) materials have proven very attractive with high brightness, ambient condition operation, and site-specific engineering. Integrating single photons in 2D hosts with photonic circuits is a central building block for quantum photonics to enhance spectral properties, light-matter interactions, and indistinguishability. Here, we present novel prototypes for integrating room-temperature single-photon emitters in hexagonal boron nitride (hBN) to low-loss, low-emission silicon nitride photonic integrated circuits. Our platform features an optimized approach that couples more than 50% of the generated single-photons to the waveguide's optical mode, microring resonators for Purcell enhancement, and chip-to-fiber coupling. Additionally, a precise alignment of the quantum defects is achieved by combining two sets of global and local alignment marks enabling diffraction-limited accuracy of their positioning on the target chip. This integrated platform is a vital step towards scalable photonic quantum circuits. In the future, the Stark effect can be exploited for efficient spectral tunability, enabling a deterministic control of the single photon's spatio-temporal and spectral properties and their coupling to resonators.