Programmable frequency-bin quantum states in a nano-engineered silicon device

TL;DR

This paper presents a silicon nano-photonic chip capable of generating and manipulating frequency-bin entangled photons, combining programmability, high brightness, and compatibility with optical networks for quantum communication.

Contribution

It introduces a programmable silicon chip that produces frequency-bin entangled states, enabling on-chip control and integration for quantum information processing.

Findings

Able to generate all four computational basis states.

Capable of producing all four Bell states.

Maintains high fidelity and purity of quantum states.

Abstract

Photonic qubits should be controllable on-chip and noise-tolerant when transmitted over optical networks for practical applications. Furthermore, qubit sources should be programmable and have high brightness to be useful for quantum algorithms and grant resilience to losses. However, widespread encoding schemes only combine at most two of these properties. Here, we overcome this hurdle by demonstrating a programmable silicon nano-photonic chip generating frequency-bin entangled photons, an encoding scheme compatible with long-range transmission over optical links. The emitted quantum states can be manipulated using existing telecommunication components, including active devices that can be integrated in silicon photonics. As a demonstration, we show our chip can be programmed to generate the four computational basis states, and the four maximally-entangled Bell states, of a two-qubits system. Our device combines all the key-properties of on-chip state reconfigurability and dense integration, while ensuring high brightness, fidelity, and purity.