Unidirectional efficient hybrid coupler for an integrated single-photon source

Abstract

Hybrid integrated quantum photonic circuits possess the potential to scale up the number of quantum nodes with distributed quantum-information-processing units at affordable resources. One of the key requirements is to achieve high-efficiency and unidirectional coupling of single quantum emitters into the low loss dielectric photonic waveguide modes. Plasmonic waveguides have the capability to have high coupling efficiency due to enhanced light–matter interactions. However, they suffer from significant propagation losses. Here we design and numerically demonstrate an on-chip hybrid plasmonic–photonic integrated single-photon source that enhances the emission rate of a quantum emitter and possesses unidirectional emission to a waveguide with high coupling efficiency. Currently, the emission rate of the single emitter is enhanced by a factor of 20, and the coupling efficiency from the single emitter into the photonic circuit exceeds 70%. The integrated hybrid single-photon source could find applications in quantum-information technologies.