Parametric down-conversion photon pair source on a nanophotonic chip

TL;DR

This paper demonstrates an integrated on-chip photon pair source using Aluminum nitride microring resonators, showing high brightness, low noise, and potential for scalable quantum photonic circuits.

Contribution

It presents the first on-chip parametric down-conversion source based on second order nonlinearity in Aluminum nitride microring resonators, advancing integrated quantum photonics.

Findings

High-visibility antibunching of heralded single photons

Photon pairs generated at MHz-rates with high coincidence-to-accidental ratio

Spectrally separated photon pairs suitable for integration

Abstract

Quantum photonic chips, which integrate quantum light sources alongside active and passive optical elements, as well as single photon detectors, show great potential for photonic quantum information processing and quantum technology. Mature semiconductor nanofabrication processes allow for scaling such photonic integrated circuits to on-chip networks of increasing complexity. Second order nonlinear materials are the method of choice for generating photonic quantum states in the overwhelming part of linear optic experiments using bulk components but integration with waveguide circuitry on a nanophotonic chip proved to be challenging. Here we demonstrate such an on-chip parametric down-conversion source of photon pairs based on second order nonlinearity in an Aluminum nitride microring resonator. We show the potential of our source for quantum information processing by measuring high-visibility antibunching of heralded single photons with nearly ideal state purity. Our down conversion source operates with high brightness and low noise, yielding pairs of correlated photons at MHz-rates with high coincidence-to-accidental ratio. The generated photon pairs are spectrally far separated from the pump field, providing good potential for realizing sufficient on-chip filtering and monolithic integration of quantum light sources, waveguide circuits and single photon detectors.