Narrow and broadband single-photon sources using customised-tapered waveguides

TL;DR

This paper investigates how customized-tapered waveguides can be used to create single-photon sources with tunable spectral widths, optimizing their efficiency and spectral purity through different tapering profiles.

Contribution

It introduces a model for designing tapered waveguides that optimize single-photon spectral properties and identifies the waveguide length for maximum spectral purity.

Findings

Tapering profiles can produce narrow or broadband single-photon sources.

Optimal waveguide length maximizes spectral purity.

Tapered waveguides significantly enhance four-wave mixing efficiency.

Abstract

In this paper, we present a thorough investigation for a spontaneous parametric four-wave mixing process in third-order nonlinear waveguides with various continuous tapering patterns. It has been previously shown that these devices can quasi-phase-match the four-wave-mixing process and enhance its conversion efficiency by orders of magnitude. By altering the tapering profile curve we found that these devices can enable single-photon sources with either narrow or broadband spectral widths at on-demand frequencies. Using our model, we were also able to identify the waveguide length at which the single-photon spectral purity is maximised.