On‐Chip Integration of Single Photon Sources via Evanescent Coupling of Tapered Nanowires to SiN Waveguides

Abstract

AbstractA method to integrate nanowire‐based quantum dot single photon sources on‐chip using evanescent coupling is demonstrated. By deterministically placing an appropriately tapered III‐V nanowire, containing a single quantum dot, on top of a silicon‐based ridge waveguide, the quantum dot emission directed toward the taper can be transferred to the ridge waveguide with calculated efficiencies close to 100%. As the evanescent coupling is bidirectional, the source can be optically pumped in both free‐space and through the ridge waveguide. The latter configuration paves the way toward a self‐contained, all‐fiber, plug‐and‐play solution for applications requiring a bright on‐demand single photon source. Using InAsP quantum dots embedded in InP nanowire waveguides, coupling efficiencies to a SiN ridge waveguide of 74% with a single photon purity of 97% are demonstrated. The technique to demonstrate deterministic placement of single quantum emitters onto pre‐fabricated waveguides is used, an important step toward the fabrication of complex quantum photonic circuits.