Near-unity efficiency in ridge waveguide-based, on-chip single-photon sources

Abstract

We report a numerical design procedure for pursuing a near-unity coupling efficiency in quantum dot-cavity ridge waveguide single-photon sources by performing simulations with the finite element method. Our optimum design which is based on a 1D nanobeam cavity, achieves a high source efficiency ${\epsilon }_{xy}$ of 97.7$\%$ for an isotropic in-plane dipole, together with a remarkable Purcell factor of 38.6. Such a good performance is mainly attributed to the high index contrast of GaAs/SiO${}_2$ and a careful cavity design achieving constructive interference and low scattering losses. Furthermore, we analyze the bottleneck of the proposed platform, which is the mode mismatch between the cavity mode and the Bloch mode in the nanobeam. Accordingly, we present the optimization recipe of an arbitrarily high-efficiency on-chip single-photon source by implementing a taper section, whose high smoothness is beneficial to gradually overcoming the mode mismatch, and therefore leading to a higher Purcell factor and source efficiency. Finally, we see good robustness of the source properties in the taper-nanobeam system under the consideration of realistic fabrication imperfections on the hole variation.

References in corpus (7)

• Photonic quantum technologies
• Optical Quantum Computing
• Experimental realization of highly-efficient broadband coupling of single quantum dots to a photonic crystal waveguide
• Scalable integrated single-photon source
• Tailoring solid-state single-photon sources with stimulated emissions
• Numerical Investigation of Light Emission from Quantum Dots Embedded into On-Chip, Low Index Contrast Optical Waveguides
• Design and fabrication of ridge waveguide-based nanobeam cavities for on-chip single-photon sources