Three-dimensional entanglement on a silicon chip

TL;DR

This paper demonstrates a silicon photonic chip capable of generating, manipulating, and analyzing high-quality three-dimensional entangled photon states, advancing integrated quantum photonics for complex quantum information tasks.

Contribution

It introduces a novel silicon chip with interferometric sources and reconfigurable circuits for high-dimensional entanglement, quantum nonlocality tests, and quantum simulations.

Findings

High-visibility quantum interference above 96.5%

Maximum entangled qutrit state fidelity of 95.5%

Successful implementation of quantum nonlocality and phase measurements

Abstract

Entanglement is a counterintuitive feature of quantum physics that is at the heart of quantum technology. High-dimensional quantum states offer unique advantages in various quantum information tasks. Integrated photonic chips have recently emerged as a leading platform for the generation, manipulation and detection of entangled photons. Here, we report a silicon photonic chip that uses novel interferometric resonance-enhanced photon-pair sources, spectral demultiplexers and high-dimensional reconfigurable circuitries to generate, manipulate and analyse path-entangled three-dimensional qutrit states. By minimizing on-chip electrical and thermal cross-talk, we obtain high-quality quantum interference with visibilities above 96.5% and a maximumly entangled qutrit state with a fidelity of 95.5%. We further explore the fundamental properties of entangled qutrits to test quantum nonlocality and contextuality, and to implement quantum simulations of graphs and high-precision optical phase measurements. Our work paves the path for the development of multiphoton high-dimensional quantum technologies.