# Monolithic integration of single photon sources via evanescent coupling of tapered InP nanowires to SiN waveguides

## TL;DR

This paper presents a monolithic integration method for nanowire-based quantum dot single photon sources on silicon nitride waveguides via evanescent coupling, achieving high efficiency and purity for on-chip quantum photonics.

## Contribution

It introduces a deterministic placement technique for tapered III-V nanowires on silicon waveguides, enabling efficient, bidirectional evanescent coupling of single photon sources.

## Key findings

- Coupling efficiency of 74% to SiN waveguides.
- Single photon purity of 97%.
- Demonstration of a self-contained, all-fiber single photon source.

## Abstract

We demonstrate a method to monolithically integrate nanowire-based quantum dot single photon sources on-chip using evanescent coupling. By deterministically placing an appropriately tapered III-V nanowire waveguide, containing a single quantum dot, on top of a silicon-based ridge waveguide, the quantum dot emission 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 onfiguration provides a self-contained, all-fiber, single photon source suitable as a plug-and-play solution for applications requiring bright, on-demand single photons. Using InAsP quantum dots embedded in InP nanowire waveguides, we demonstrate coupling efficiencies to a SiN ridge waveguide of 74% with a single photon purity of 97%.