Scalable and highly efficient approach for an on-chip single-photon source

Integrated photonic circuits with quantum dots provide a promising route for scalable quantum chips with highly efficient photonic sources. However, unpolarized emission photons in general sacrifice half efficiency when coupling to the waveguide fundamental mode by a cross polarization technique for suppressing the excitation laser, while suspended waveguide photonics sources without polarization filters have poor scalability due to their mechanical fragility. Here, we propose a strategy for overcoming the challenge by coupling an elliptical Bragg resonator with waveguides on a solid-state base, featuring near-unity polarization efficiency and enabling on-chip pulsed resonant excitation without any polarization filters. We theoretically demonstrate that the proposed devices have outstanding performance of a single-photon source with 80% coupling efficiency into on-chip planar waveguides and an ultra-small extinction ratio of 10 − 11 , as well as robustness against quantum dot position deviation. Our design provides a promising method for scalable quantum chips with a filter-free high-efficiency single-photon source.