Generation of hyperentangled photon pairs in the time and frequency domain on a silicon photonic chip

TL;DR

This paper demonstrates the first generation of hyperentangled photon pairs in time and frequency domains on a silicon photonic chip, enhancing quantum communication capabilities with integrated technology.

Contribution

It introduces a novel integrated silicon photonic device capable of generating and verifying hyperentangled photon pairs in multiple degrees of freedom.

Findings

Successful violation of CHSH inequality in each DoF

Verification of genuine hyperentanglement with high statistical significance

First demonstration of time-frequency bin hyperentanglement on silicon chip

Abstract

Multi-dimensional entangled photon states represent an important resource in quantum communication networks. Specifically, hyperentangled states presenting simultaneous entanglement in several degrees of freedom (DoF), stand out for their noise resilience and information capacity. In this work, we demonstrate the generation of hyperentangled photon pairs in the time and frequency-bin domain by spontaneous four-wave mixing from the coherent driving of two integrated Silicon microresonators. We demonstrate entanglement in each DoF by proving the violation of the Clauser Horne Shimony Holt (CHSH) inequality by more than 27 standard deviations (STDs) in each reduced space. Genuine hyperentanglement is then assessed from the negativity of an hyperentanglement witness, which is verified by more than 60 STDs. These results mark, to the best of our knowledge, the first demonstration of time-frequency bin hyperentanglement in an integrated silicon photonic device.