Photonic integrated chip enabling orbital angular momentum multiplexing for quantum communication

TL;DR

This paper introduces a silicon photonic chip capable of generating and manipulating orbital angular momentum modes for quantum communication, enabling multiplexing and parallel quantum key distribution in a compact, scalable device.

Contribution

The work demonstrates the first integrated silicon chip that excites orbital angular momentum modes in fiber, advancing scalable quantum communication technologies.

Findings

Successfully performed parallel quantum key distribution with multiple OAM modes

Demonstrated excitation of OAM modes in an 800 m fiber using the chip

Pushed forward the development of integrated devices supporting OAM modes

Abstract

Light carrying orbital angular momentum constitutes an important resource for both classical and quantum information technologies. Its inherently unbounded nature can be exploited to generate high-dimensional quantum states or for channel multiplexing in classical and quantum communication in order to significantly boost the data capacity and the secret key rate, respectively. While the big potentials of light owning orbital angular momentum have been widely ascertained, its technological deployment is still limited by the difficulties deriving from the fabrication of integrated and scalable photonic devices able to generate and manipulate it. Here, we present a photonic integrated chip able to excite orbital angular momentum modes in an 800 m long ring-core fiber, allowing us to perform parallel quantum key distribution using 2 and 3 different modes simultaneously. The experiment sets the first steps towards quantum orbital angular momentum division multiplexing enabled by a compact and light-weight silicon chip, and further pushes the development of integrated scalable devices supporting orbital angular momentum modes.