Quantum Multiplexing with the Orbital Angular Momentum of light

TL;DR

This paper introduces two innovative optical setups leveraging the orbital angular momentum of photons to multiplex multiple quantum communication channels over a single free-space link, enhancing capacity without interference.

Contribution

It presents novel optical configurations for quantum multiplexing using OAM, enabling simultaneous multi-user communication sharing the same optical path, wavelength, and polarization.

Findings

Two new optical multiplexing setups demonstrated.

Multiplexing increases quantum communication capacity.

Potential applications include quantum arithmetic and OAM sorting.

Abstract

The orbital angular momentum, OAM, of photons offers a suitable support to carry the quantum data of multiple users. We present two novel optical setups that send the information of n quantum communication parties through the same free-space optical link. Those qubits can be sent simultaneously and share path, wavelength and polarization without interference, increasing the communication capacity of the system. The first solution, a qubit combiner, merges n channels into the same link, which transmits n independent photons. The second solution, the OAM multiplexer, uses CNOT gates to transfer the information of n optical channels to a single photon. Additional applications of the multiplexer circuits, such as quantum arithmetic, as well as connections to OAM sorting are discussed.