Optical fibre-based single photon source using InAsP quantum dot nanowires and gradient-index lens collection

David B Northeast; Dan Dalacu; John F Weber; Jason Phoenix; Jean Lapointe; Geof C Aers; Philip J Poole; Robin L Williams

doi:10.1038/s41598-021-02287-y

Optical fibre-based single photon source using InAsP quantum dot nanowires and gradient-index lens collection

Sci Rep. 2021 Nov 24;11(1):22878. doi: 10.1038/s41598-021-02287-y.

Authors

David B Northeast^#¹, Dan Dalacu^#², John F Weber², Jason Phoenix^{2

3}, Jean Lapointe², Geof C Aers², Philip J Poole², Robin L Williams²

Affiliations

¹ National Research Council Canada, Ottawa, ON, K1A 0R6, Canada. david.northeast@nrc-cnrc.gc.ca.
² National Research Council Canada, Ottawa, ON, K1A 0R6, Canada.
³ University of Waterloo, Waterloo, N2L 3G1, Canada.

^# Contributed equally.

Abstract

We present a compact, fibre-coupled single photon source using gradient-index (GRIN) lenses and an InAsP semiconductor quantum dot embedded within an InP photonic nanowire waveguide. A GRIN lens assembly is used to collect photons close to the tip of the nanowire, coupling the light immediately into a single mode optical fibre. The system provides a stable, high brightness source of fibre-coupled single photons. Using pulsed excitation, we demonstrate on-demand operation with a single photon purity of 98.5% when exciting at saturation in a device with a source-fibre collection efficiency of 35% and an overall single photon collection efficiency of 10%. We also demonstrate "plug and play" operation using room temperature photoluminescence from the InP nanowire for room temperature alignment.