Frequency auto-homogenization using group-velocity-matched downconversion

TL;DR

This paper introduces a method for removing spectral distinguishability in single-photon sources using frequency auto-homogenization via group-velocity-matched downconversion, enhancing scalability in photonic quantum information processing.

Contribution

It presents a novel frequency auto-homogenization technique based on group-velocity-matched downconversion to improve photon indistinguishability in integrated quantum photonics.

Findings

Theoretical framework using $5^{(2)}$ quantum frequency conversion.

Proof-of-principle experimental demonstration in free-space setup.

Potential to enable scalable quantum networks with identical photons.

Abstract

With the stability of integrated photonics at network nodes and the advantages of photons as flying qubits, photonic quantum information processing (PQIP) makes quantum networks increasingly scalable. However, scaling up PQIP requires the preparation of many identical single photons which is limited by the spectral distinguishability of integrated single-photon sources due to variations in fabrication or local environment. To address this, we introduce frequency auto-homogenization via group-velocity-matched downconversion to remove spectral distinguishability in varying quantum emitters. We present our theory using $\chi^{(2)}$ quantum frequency conversion and show proof-of-principle data in a free-space optical setup.